User Manual AM700 Audio Measurement Set with Color Display 070-9585-01 This document applies to firmware version 1.02 and above.
The following copyright covers this manual for the AM700. Copyright Tektronix, Inc. All rights reserved. Printed in the United States of America. Contents of this publication may not be reproduced in any form without the written permission of Tektronix, Inc. Information in this publication supersedes that in all previously published material. Specifications and price change privileges reserved. The following are registered trademarks: TEKTRONIX and TEK.
The following copyright covers the TIFF Code used in the AM700. Source code is not provided. Copyright (c) 1988, 1989, 1990, 1991, 1992 Sam Leffler Copyright (c) 1991, 1992 Silicon Graphics, Inc.
WARRANTY Tektronix warrants that this product will be free from defects in materials and workmanship for a period of one (1) year from the date of shipment. If any such product proves defective during this warranty period, Tektronix, at its option, either will repair the defective product without charge for parts and labor, or will provide a replacement in exchange for the defective product.
EC Declaration of Conformity We Tektronix Holland N.V. Marktweg 73A 8444 AB Heerenveen The Netherlands declare under sole responsibility that the AM700 Audio Measurement Set meets the intent of Directive 89/336/EEC for Electromagnetic Compatibility.
Table of Contents General Safety Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xiii Introduction and Installation Key Features of the AM700 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Operation and Controls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Measurement Capability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Table of Contents Menu . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Limits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Rescale . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Freeze . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Filter . . . . . . . . .
Table of Contents Keypad Entry Buttons . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Units Key . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Set Ref Key . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Front Panel Lock and Unlock . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Front-Panel Signal Connectors . . . . .
Table of Contents iv Generator Selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Assigning Control Knobs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Specifying an Output Waveform . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Multitone Files . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Enabling Generator Output . . . . . . . . . . . .
Table of Contents Controlling Plotted Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Enable . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . History . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Begin New Plot . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Erase All Plots . . . . .
Table of Contents Input Select . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Trigger Selects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-103 4-104 Digital Interface Tester . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Digital Interface Tester Input Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . View Setup .
Table of Contents List of Figures Figure 1-1: Rear panel fuse, power connector, On/Off Switch, and line selector . . . . . . . . . . . . . . . . . Figure 1-2: Application selection menu under the Other button . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Figure 1-3: Touch screen calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Figure 1-4: AM700 System Clock . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Table of Contents Figure 2-30: GPIB connector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Figure 2-31: Remote contact-closure connector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Figure 2-32: Digital audio connectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Figure 2-33: Digital signal processor port connector . . . . . . . . . . . . . . . . . . . . . . . .
Table of Contents Figure 4-16: General controls with Regulation mode menu selections . . . . . . . . . . . . . . . . . . . . . . . . Figure 4-17: Regulation mode with Plot Control menu . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Figure 4-18: View Setup for Regulation mode measurements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Figure 4-19: Regulation mode bandpass measurement of level versus frequency . . . . . . . . . . . . . . . .
Table of Contents Figure 4-49: Dual channel display showing different signals on Channel 1 and Channel 2 . . . . . . . . . . Figure 4-50: The View Setup screen for Audio Monitor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Figure 4-51: View Options in the View Setup controls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Figure 4-52: Use of Cursors to measure pulse time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Table of Contents List of Tables Table 1-1: Optional Power Cords . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Table 3-1: Quick Setups by Application . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Table 4-1: Subframe Time Slots . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Table A-1: Analog Analyzer Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Table of Contents xii AM700 Audio Measurement Set
General Safety Summary Review the following safety precautions to avoid injury and prevent damage to this product or any products connected to it. Only qualified personnel should perform service procedures. To avoid potential hazards, use this product only as specified. Injury Precautions Use Proper Power Cord To avoid fire hazard, use only the power cord specified for this product.
General Safety Summary Do Not Operate in Wet/Damp Conditions Do Not Operate in Explosive Atmosphere To avoid electric shock, do not operate this product in wet or damp conditions. To avoid injury or fire hazard, do not operate this product in an explosive atmosphere. Product Damage Precautions Use Proper Power Source Use Proper Voltage Setting Provide Proper Ventilation Do Not Operate With Suspected Failures Do not operate this product from a power source that applies more than the voltage specified.
General Safety Summary CAUTION. Caution statements identify conditions or practices that could result in damage to this product or other property. Terms on the Product These terms may appear on the product: DANGER indicates an injury hazard immediately accessible as you read the marking. WARNING indicates an injury hazard not immediately accessible as you read the marking. CAUTION indicates a hazard to property including the product.
General Safety Summary xvi AM700 Audio Measurement Set User Manual
Introduction and Installation
Introduction and Installation The Tektronix AM700 Audio Measurement System is a programmable, highperformance, mixed signal audio analyzer designed for use in product design, characterization, quality control, manufacturing test, and servicing. The AM700 is also a valuable tool for monitoring and testing of signal distribution systems used in broadcasting and related applications.
Introduction and Installation H The SOUND function in all applications (except Digital Interface Tester) allows monitoring of signals through headphones. H The physical size of the AM700 is approximately 7.7 inches high, 18.2 inches wide (with handle), 18.8 inches deep, and it weighs about 31 pounds. This size allows the instrument to fit laboratory bench space and enhances portability.
Introduction and Installation a cluttered viewing area. The display screens can be formatted for any external PostScript, Laserjet, or Epson-compatible printer for generating printed copies of the measurements and waveforms. Graphic images in PostScript and TIFF formats can be formatted for color copy. The AM700 has a unique view window feature that lets you view multiple graphical measurement displays.
Introduction and Installation The digital generator is also very flexible. It can produce test signals in AES/EBU, SPDIF, Optical, and raw data forms at a variety of sample rates. Like the analog generator, it can produce independent signals on either channel. In addition to the audio test signals, you can use this generator to manipulate the Channel Status Data and User Data bits in the serial data stream.
Introduction and Installation Power connector On/Off switch Fuse Line selector Figure 1-1: Rear panel fuse, power connector, On/Off Switch, and line selector Changing the Line Voltage Range and Fuse The AM700 is shipped from the factory set for the operating voltage of the destination country (115 VAC or 230 VAC). If the setting is not correct, it must be changed before connecting the power cord to the power source. 1.
Introduction and Installation The mains fuse provides protection in the event of a major failure of the AM700 power supply. Two sizes of fuses are specified, one for 115 V operation and the other for 230 V operation. Refer to Fuse Rating on page A-27 of Appendix A for the correct fuse rating to use for each voltage range. 3. Replace the fuse with the correct one, as indicated on the rear panel, for the new mains voltage selection. CAUTION. Use only the power cord and connector specified for your product.
Introduction and Installation Should a power-up diagnostic fail, the AM700 should be referred to your local Tektronix representative for servicing. Should the AM700 go into a continuous reset condition, refer to Appendix A of the AM700 Programmer Manual for the procedure used to clear the NVRAM of possible undefined states. Table 1-1: Optional Power Cords Power Plugs Description Standard North American 120 V plug Reference Standards1 ANSI C73.11 NEMA 5-15-P IEC 83 UL 198.
Introduction and Installation Calibrating the Touch Screen The AM700 is shipped from the factory with its touch screen fully calibrated. Although it will seldom be necessary, the touch screen can easily be recalibrated. To calibrate the touch screen: H Press the front-panel button labeled “Other.” H Use the large control knob to scroll through the menu choices and select the touch screen calibration choice from the menu that appears (see Figure 1-2). Press Enter on the keypad to activate the selection.
Introduction and Installation Full instructions for calibration are given on the screen when the calibration display appears (see Figure 1-3). H A small circle with a dot is highlighted in succession in each of three corners. View the screen directly on to avoid parallax errors and use a small blunt pointed tool, such as a pencil eraser tip, to produce the best accuracy for the calibration. Touch the screen directly over the first dot. The dot in the next corner then lights.
Introduction and Installation H Setting the AM700 Clock Press any application front-panel button to exit the paint screen and start the application. The AM700 has a system clock with an internal backup battery. After setting for your local time, it is ready to use. Performing this exercise for the first time will also introduce you to the Configure menus that you will use as you set up the AM700. To set the clock use the following procedure: 1. Press the Configure button on the front panel.
Introduction and Installation 3. Check the date and time settings. If any are not correct, select them individually to adjust to the correct setting. A selected choice changes intensity to show that editing of that setting is active. 4. Set the correct number by rotating the large control knob or by entering the correct number with a direct keypad entry and pressing the Enter button.
Introduction and Installation Standard Accessories H AM700 User Manual H AM700 Programmer Manual H AM700 Programmer Quick Reference Manual H Standard power cord (optional power cord substituted when ordered) H Front Cover Optional Accessories Accessories can be used for remote control, signal interfacing, and rackmounting.
Operating Basics
Operating Basics This section describes the AM700 user interface and connections and introduces basic instrument operations. Topics discussed in this section include: front-panel controls, touch-screen interface, and analog and digital connections. This section also describes the basic operations that must be performed while using the AM700 for audio measurement and analysis.
Operating Basics Many AM700 operations are started by selecting soft keys (shown in Figure 2-2) using the touch screen (touching the display in the right place to invoke some function). In some menus, numerical values are entered either from the keypad or with the control knob. Front panel buttons with gold outlines (Copy, Average, Cursor, Sound, Filter, Sound On, User, and Units) have two possible behaviors, depending on how you use them and the application or display that is running.
Operating Basics Application name Input signal source Submenu bar appears when a Main Menu selection is made. Main Menus appear when the front-panel menu button is pressed. When selected, the button is highlighted. Figure 2-2: Touch screen interface with main menus and submenus displayed NOTE. When menus or soft key selections are grayed out, it means those choices are not currently available for selection.
Operating Basics Application Control An AM700 application is started by pressing a button (if it has a dedicated front-panel button) or by selecting it from the menu displayed when the “Other” front-panel button is pressed and released. Each AM700 measurement application corresponds functionally to a dedicated measurement instrument. The AM700 runs one measurement application at a time. The Generator is independent of the application and maintains its settings between applications.
Operating Basics DISPLAY VIEW GENERATOR STATUS READOUT REAL TIME MEASUREMENTS TWO OR MORE CHOICES ARE TOGGLED A LIST OF CHOICES IS AVAILABLE CHOICE IS SELECTED CHOICE IS NOT SELECTED SELECTION IS ENABLED SELECTION IS NOT ENABLED MOVE OR EXPAND HORIZONTALLY MOVE OR EXPAND VERTICALLY HORIZONTAL ZOOM POINT VERTICAL ZOOM POINT LARGE CONTROL KNOB GENERATOR KNOBS ASSIGNED Figure 2-3: Representative icons and arrows seen in the AM700 display AM700 Audio Measurement Set User Manual 2-5
Operating Basics Figure 2-4: Views selection bar with only View 1 selected for display When multiple view windows are displayed (including the RT and Generator Status views), assigning the controls to a particular view is done by touching the screen in that view. The touched view then becomes the active view and is indicated by a brighter border around that view window as shown in Figure 2-5. Cursor controls and the move/expand action are directed to the traces in the active view.
Operating Basics Real-Time Readout view window Bright border indicates the view window that has the control focus. Generator Status view window Figure 2-5: View windows and control assignment Measurement Units You can also select the units in which the data is displayed. These unit selections apply to measurement readouts, parameter settings, and graphical display axes. Where appropriate, the following units choices are available.
Operating Basics Front-panel Operation The AM700 front panel consists of a touch screen, selections buttons and control knobs divided into functional control areas, and a numeric keypad. Figure 2-6 illustrates the front panel of the AM700. Figure 2-6: AM700 front panel Front Panel Button General Information 2-8 Many of the front panel button labels have back lights. These back lights are on to light up a button label when the selection for that button is active.
Operating Basics System Control Buttons The System Control buttons shown in Figure 2-7 provide control of function that are not application specific. In general the system functions are available for use with all the applications. Figure 2-7: System control buttons Menu Pressing the Menu button displays the soft key controls that are available for the application currently in use. Limits The Limits feature of the AM700 has not been activated.
Operating Basics Freeze Pressing the Freeze button (a toggle) halts display updates. Some frozen displays cam be expanded horizontally and vertically. When expanding a frozen display, the AM700 interpolates acquired data to provide display points for the expanded displays. Also, cursors can be used on the frozen display to make measurements. Display updates are resumed when Freeze is pressed a second time.
Operating Basics Pressing and holding the Cursor button brings up the Cursor menu as shown in Figure 2-8. The menu controls permit you to select cursors and employ some special positioning actions. Figure 2-8: Cursor menu showing frequency and level readouts Next Cursor. Next Cursor toggles the active cursor selection between the two cursors. Cursor 1 is indicated as a solid vertical line; cursor 2 is indicated as a dashed vertical line. The active cursor is brightened.
Operating Basics Snap to Data. Snap to Data, when enabled, causes the cursors to be positioned from data point to data point (not interpolated points) in the trace. When not enabled, cursors are not held to the acquired data points and they are positioned smoothly along the trace. Next Peak and Previous Peak. The Next Peak and Previous Peak soft keys are available with either cursor active.
Operating Basics With the Average menu displayed, touch the Avg Count soft key to activate the field editor and either use the control knob to adjust the number or use the numeric keypad to enter a new average count number. The Avg Count can be set for 1 to 9,999 averages. Touch the Processing soft key and turn the control knob to specify averaging or holding minimum or maximum signal values. Touch the Processing soft key to accept the change.
Operating Basics Applications Buttons The AM700 applications are introduced here. Refer to Applications beginning on page 4-1 for detailed information on each application. Operation of the generator is included in the applications information, followed by the Analyzer, FFT, Digital, Monitor, and Functions, in that order. The buttons in the Applications area control, shown in Figure 2-10, provide access to AM700 measurement applications. You can start an application by pressing its button.
Operating Basics Analyzer The Audio Analyzer application accepts analog or digital audio input signals for analysis. This application makes the following measurements: H Signal Level and Frequency H Stereo Phase Difference H Level Difference H THD (total harmonic distortion) H THD + N (total harmonic distortion plus noise) H IMD (intermodulation distortion) H Crosstalk + noise H Channel separation H Wow and Flutter Refer to Audio Analyzer beginning on page 4-37 for more information.
Operating Basics FFT Analyzer The FFT Analyzer has both FFT Measurement and Multitone Measurement applications. FFT Measurements. The FFT Analyzer can display two channels simultaneously. These displays can either be on separate frequency and amplitude axes or overlaid onto the same frequency and amplitude axes. Using any combination of analog and digital inputs set up in the Configure menu, the FFT Analyzer produces displays of frequency domain data much like those of a spectrum analyzer.
Operating Basics Utilities Buttons Utility buttons, shown in Figure 2-11, activate and control these support functions: Configure, Display, Storage, Copy, and Function. Figure 2-11: Utilities buttons Configure Pressing this button displays soft keys that provide access to various system configuration menus. Refer to AM700 Setup for Operation beginning on page 3-1 for more information on the configure choices. Quick Setup. Touch this soft key to display a menu of template selections.
Operating Basics System Setup. Touch this soft key to display the System Setup menu. Soft keys in this display allow you to set the date and time, configure the serial and GPIB communications parameters, select copy format and destination for display captures, activate calibration, and specify the external input and output resistance values to be used for units conversions between volts, dBu, and dBm, and to specify the conversion factor to dBFS. View Setup.
Operating Basics Figure 2-12: System Status display Display When the Display button is pressed and held, the large control knob adjusts the display intensity. Display intensity values range from about 10% for full dim to 100% for full brightness. The power on default setting for display intensity is 90%. When the display brightness is reduced to 40% or lower, pressing the Display button immediately sets the brightness to 90%.
Operating Basics Function files and user files written on an external PC can be downloaded to the appropriate NVRAM directory for use. The Storage Manager detects the presence of a floppy disk in the disk drive. If file names from the dos: directory are being displayed when the disk is removed, another directory list (either rom: or nvram:) is displayed instead. Renaming a File. When you want to rename a file, select that file and touch the Rename soft key.
Operating Basics Figure 2-14: File renaming keyboard Copy Pressing the Copy button sends a copy of the display in the selected format to the print spooler (temporary memory space) where it is queued for printing. The LED in the Copy button flashes as long as the copy remains in the spooler. To select the output format for a copy, you must use the menu selections for Copy found in the Configure menu under System Setup. Refer to System Copy on page 3-13 for information on setting up the Copy choices. NOTE.
Operating Basics Function Functions are pre-programmed routines residing in AM700 memory. Refer to the AM700 Programmer manual and Function Operation beginning on page 4-129 for further information on programming functions. Running a Function. You can run stored functions from the front panel using menu choices selected with the Function button. 1. Press the Function button to display the menu of available functions. 2.
Operating Basics Control Knob and Display Control Buttons Control Knob The control knob, shown in Figure 2-15, lets you perform positioning, selection, or expansion. Control knob operation depends on the current instrument operating mode, and its functions are described as a part of instrument operations. Figure 2-15: Control knob and display control buttons The general operation of this knob is to permit continuously variable positioning or selection when user selections are active.
Operating Basics Touch and Zoom. You can select the expansion point by touching the screen where you want it to expand. This is the Touch and Zoom feature. In this case, the selected (highlighted) axis is assumed to be the expansion axis. You can use the Select front-panel button to switch between the axes. The expansion point is marked by a small arrow on the graticule scale of the axis that will expand or contract when you turn the control knob.
Operating Basics Generator Control Knobs and Buttons The Amplitude and Frequency knobs shown in Figure 2-16 provide easy access for controlling the generator, regardless of the state of the instrument or current control function of the general purpose knob. Figure 2-16: Audio Generator controls Amplitude and Frequency Knobs The Amplitude and Frequency knobs are both assigned to one generator output at a time or, when the generators are set to Follow, the knobs also affect all following generators.
Operating Basics Control Press this button to display the Generator Control menu (see Figure 2-17). Refer to Audio Generator on page 4-1 for complete details on the Generator Control panel.
Operating Basics Audio Control Knob, Button, and Headphones Figure 2-18: Headphone audio controls On Button Pressing and releasing the On button turns sound on to the headphones. When Sound is on, the AM700 stops making measurements. Pressing and holding the On button displays the Sound source menu where you can select either Digital or Analog as the source to listen to with the headphones.
Operating Basics Sweep / Run Button Figure 2-19: Sweep/Run button and LED indicator Sweeps When you press the Sweep/Run button or when the AM700 receives a remote Start trigger event, the generator turns on (if it was not already on), and all applicable sweeps are started. Set the sweep count number to make a selected number of sweeps or set the sweep count number to 0 to run the sweep continually. At the end of the set number of sweeps for all enabled sweeps, the generator stops sweeping.
Operating Basics Keypad Entry Buttons Figure 2-20: Keypad entry buttons The keypad is used to make numerical input to the menus, set units on readouts and graphical display axes, and in setting a reference. When numerical values are selected for editing, numbers can be entered directly using the number keys and the Enter key. The number in the field being editing is erased as the first keypad number is pressed.
Operating Basics When you have selected the unit you want used for a readout, touch the select button or, if a pop-up menu is displayed, touch the menu to make the selection. In the column beneath the Units button are units choices for the more common selections. These buttons can be used to select V, Hz, mV, kHz, or dBu directly. Additional choices are available in the pop-up menu. The numerical value of the measurement also changes to reflect the selected units.
Operating Basics Front-Panel Signal Connectors Figure 2-21: Front-panel signal connectors Specifications for the input and output connectors and signals are found in Appendix A, Specifications. Pin outs for the Analog XLR connectors are shown in Figure 2-22. Analog Out The internal analog generator output signals are present on these XLR connectors when the generator is active. The Channel A and Channel B outputs are independently buffered and can be independently enabled.
Operating Basics single-ended loads. The generator output level driving an unbalanced load will be half of the indicated value (6 dB less), and the source resistance will be half the selected output impedance value. For example, if the selected output impedance of the generator is 10 Ω, the single-ended output source impedance is 5 Ω nominal.
Operating Basics Configurations using unbalanced loads are more susceptible to ground loops. The best method for driving an unbalanced load is to use the floating ground feature of the generator. With floating ground selected, the analog output of the generator can be grounded at the load end of a signal cable, thereby reducing the effects of any ground-loop currents.
Operating Basics Floppy Disk Drive The 3.5-inch, 1.44-Meg floppy disk drive (shown in Figure 2-24) provides a means to transfer DOS-formatted files into and out of the AM700 file system. The disk drive is the dos: directory when using a File Browser or the Storage Manager control screen. Firmware upgrades are also done through the disk drive. Figure 2-24: Disk drive NOTE. The AM700 requires a preformatted disk (DOS 1.44 megabytes).
Operating Basics Rear-Panel Signal Connectors and Controls The rear panel of the AM700 is shown in Figure 2-25 to show the location of all the controls and connectors. A description of each control and connector follows. Figure 2-25: AM700 rear panel Mains Connector A detachable three-wire power cord with a three-contact plug is provided with each instrument for connecting to both the power source and protective ground.
Operating Basics Power Switch, Fuse, and Trigger These rear-panel power controls, shown in Figure 2-26, include the mains ON/OFF push button switch, the Line Selector switch for 115 or 230 VAC operation, the mains fuse holder, and the external trigger input connector. Figure 2-26: Mains connector, power switch, fuse, and line selector ON/OFF Push Button. The AM700 main power switch is on the rear panel. It is a push-push switch (push on, push off) that is on when latched in.
Operating Basics CAUTION. When changing the line voltage selector switch, to prevent damage to the AM700 you must also change the fuse to provide proper protection for the operating voltage in use. Fuse. The mains fuse provides protection in the event of a major failure of the AM700 power supply. Two sizes of fuses are specified, one for 115 VAC operation and the other for 230 VAC operation. Refer to the Fuse Rating specifications on page A-27 in Appendix A for fuse ratings. Analog Trigger Input.
Operating Basics Figure 2-28: COM1 and COM2 serial ports KYBD (Keyboard). An optional, PS/2, AT-compatible keyboard with a mini DIN connector can be attached to the KYBD connector shown in Figure 2-29. The keyboard is active whenever a parameter change or qwerty keyboard entry is expected. Using the external keyboard to make directory and file name entries makes navigating the file system faster, but one is not necessary for any AM700 operation. Figure 2-29: Keyboard and VGA video connectors VGA Video.
Operating Basics Figure 2-30: GPIB connector Refer to the AM700 Programmer Manual for information on operating with remote control. Remote Connector. This DB9 connector, shown in Figure 2-31, provides a user interface for contact-closure remote control. Its switching actions must be defined in a function to be useful for controlling the actions of the AM700. Refer to Rear Panel Hardware on page A-26 in Appendix A for pin-out information.
Operating Basics Figure 2-32: Digital audio connectors AES REF IN, OUT. These connectors meet the AES standard for AES/EBU digital audio (AES11-1991) signals. The AES REF OUT signal is locked to the AES REF IN signal in From Ref mode. This permits you to connect to your reference signal for the sample clock and provides an output that you can connect to a device under test.
Operating Basics DSP Port. You can connect a compatible digital microphone or other compatible digital signal source directly to the DSP for processing through the DSP Port connector (pinout shown in Figure 2-33). When the AM700 generator and input are set to DSP, the external device on the DSP port supplies the Bit Clock, Frame Clock, and Receive Data. When sending data, the AM700 supplies Transmit Data that is synchronized with Bit and Frame Clocks of the external device.
Operating Basics DB-15 female connector Pin 1 Pin 2 Pin 3 Pin 4 Pin 5 Pin 6 Pin 7 Pin 8 Bit Clock Receive Data Transmit Data Rate 2 Rate 1 Rate 0 +12 V –12 V Pin 9 Pin 10 Pin 11 Pin 12 Pin 13 Pin 14 Pin 15 Chassis ground Chassis ground Chassis ground Frame Sync Flag 1 Flag 0 Chassis ground Figure 2-33: Digital signal processor port connector NOTE. To meet radiated EMI regulations, the cable connected to the DSP port must be well shielded, and the connector housing must be conductive.
Operating Basics Bit Clock Frame Sync Receive Data MSB, SF1 LSB, SF1 MSB, SF2 LSB, SF2 MSB, SF1 LSB, SF1 MSB, SF2 LSB, SF2 Transmit Data Note: All Data is sampled on the falling edge of Bit Clock. Receive Data and Frame setup time before falling Bit Clock edge = 25 ns Receive Data and Frame Sync hold time before falling Bit Clock edge = 40 ns Signal level –0.5 V to +5.
Operating Basics 2-44 AM700 Audio Measurement Set User Manual
Configuring the AM700
Configuring the AM700 This section is a general discussion of how you set up the AM700 Audio Measurement Set. AM700 Setup for Operation Turn the AM700 on. Unless otherwise directed, it loads and runs the FFT Analyzer application. After the FFT Analyzer application begins running, you can select any other application you wish to use. The choices are shown in Figure 3-1. You can start an application other than FFT by pressing and holding in the front-panel button for the application you want to start.
Configuring the AM700 Configuration Press the Configuration button, shown in Figure 3-2, to display the Configuration options menu. There are seven selection choices displayed in the Configuration menu shown in Figure 3-3. Refer to Configure on page 2-17 for a summary of each of the Configuration options. Figure 3-2: Configure button in the Utilities selection block Input Selection From the Configure screen, first select Input Selection.
Configuring the AM700 Figure 3-3: Configuration menu initial selection screen Analog Input Connections. Touch the select soft key associated with the Analog A and Analog B input connections to toggle between the front-panel XLR connector and the internal Generator routing. The front-panel XLR inputs are the default choice for signal input to the AM700. Input Impedance. Analog Input Impedance is selected from a three-choice pull-down menu. The choices are 150 Ω , 600 Ω , and 200 kΩ (high).
Configuring the AM700 Input Range and Auto. The gain range for the analog inputs defaults to Auto enabled to provide auto ranging on the applied signal. This avoids possible overloading of the A/D converters and is the recommended setting for normal operation. When you know the amplitude of the signal being measured, you can choose to make a manual gain setting. Follow these steps when changing the input range setting: 1. Turn off the Auto enabling (check goes away) by touching the Auto soft key. 2.
Configuring the AM700 Input gain range settings are also available as menu choices from within the applications that make measurements on analog signals. From within a running application, you can make the change and observe the effects on the signal. Digital Input Connector Selection. The Digital Main Input connector selection choices are: Front-panel XLR connector (the most common selection and made by default), the Rear-panel BNC, and the Rear-panel Optical connector.
Configuring the AM700 Pull-down Input Selection Menu. Use the large knob to move the selection box to the signal you want. Touch the measurement channel soft key to display the pull-down menu. Touch the measurement channel soft key a second time to assign the input to the channel and clear the pull-down menu. Use the quick select soft keys to set both channels to the same generator type.
Configuring the AM700 View Setup The View Setup menu permits you to specify how measurement results should be displayed on the screen. Contents of this menu vary depending upon the current application. In the following description, the FFT application is active. View Selection Bar. The top line in the View Setup screen is a view selection bar as shown in Figure 3-6. The selections that are made in the remaining portion of the View Setup window apply only to the selected view.
Configuring the AM700 For each type of view, the AM700 also offers options that allow you to configure the display for your viewing requirements. You can configure the display in the View Setup menu (see Figure 3-6). To select a view type and define the view options: 1. Press the Configure button and touch the View Setup soft key to enter the View Setup menu. 2. Select the desired view type by touching the icon on the display. 3.
Configuring the AM700 You can set up a view to display FFT measurements or Multitone measurements but not both. The View Types that are available also depend on the measurement selected, since they are different for FFT and Multitone. The applicable choices will be displayed for the Measurement Type selected for a view. Notice that both FFT traces can be displayed in the same view window. Refer to FFT Analyzer on page 4-81, for more information about the FFT application. View Options.
Configuring the AM700 The choices in the Axes column allow the linear/log selection for the x- and y-axes and a choice of Dual Y-Axis. Dual Y-Axis displays are permitted when more than one trace is displayed in a single view. In Dual Y-Axis displays, the vertical or y-axis scale of the front trace is seen on the left side of the graticule and y-axis scale for the back trace is seen on the right side of the graticule. Other axes choices are determined by the view type.
Configuring the AM700 Measurement Setup Menu The Measurement Setup menu permits you to define which measurements are to be performed and displayed by the current application. An example of setting up different measurements in the four measurement views of Audio Analyzer is shown in Figure 3-8. Figure 3-9 shows the FFT and Multitone Measurement Setup controls. See the specific application discussions beginning on page 4-37 for information on setting up the measurements for the applications.
Configuring the AM700 FFT configure measurements Multitone configure measurements Figure 3-9: FFT Analyzer configure measurement screens for FFT and for Multitone 3-12 AM700 Audio Measurement Set User Manual
Configuring the AM700 System Setup Menu The System Setup menu is used to set the system clock, the serial and GPIB communication parameters, the hard copy output format, run the AM700 calibration routine, and set the input, output, and dBFS conversion factors. Setting the System Clock Refer to Setting the AM700 Clock on page 1-10 for a detailed procedure for setting the system clock. Select the parameter to change, then set the new number.
Configuring the AM700 Figure 3-10: The Copy Configuration menu To delete all copies from the spooler, press and hold the copy button to display the Copy Configuration menu. Touch the Cancel Pending Hardcopy soft key to delete all the spooled hard copies. The image displayed on the screen is sent to the printer when you press the Copy button. Graphic displays are printed only when the printer port is formatted for a graphics printer. Text only is sent when not formatted for a graphics printer. Copy Formats.
Configuring the AM700 When the Copy Format is either PostScript or TIFF, the Copy Style can be set to Color. When using monochrome PostScript printing, the black and white areas are color inverted to reduce the toner use for laser printers. Copy Destination. Printouts are spooled to the currently selected printer port.
Configuring the AM700 Figure 3-11: Hard copy output file selector Copy Styles. You can select the choice of color output for PostScript and TIFF formatted files. When set to Color, printer output will be color formatted. If you select a copy format other than PostScript or TIFF, the Color state is ignored, and the file is output as monochrome (gray scale) only.
Configuring the AM700 Figure 3-12: System Setup Communicate Configuration menu Saving Changes and Exiting the Input Selections Menu. Soft keys to exit the Input Selection menu are located at the bottom of the screen. When you touch the Accept Changes soft key, any selections made are entered. If you touch the Cancel soft key, all changes are deleted before returning to the current application. Pressing the Clear Menu button also exits back to the application.
Configuring the AM700 When Audio Analyzer, FFT Analyzer, or Monitor is the running application, calibration switches the analog acquisition system to a known test signal (a 120 Hz symmetrical square wave). The AM700 then acquires the positive and negative peak values seen at the output of the A and B high resolution A/D converters and at the output of the A and B high bandwidth A/D converters.
Configuring the AM700 When the generator is driving an output load of 600 Ω, and the internal series resistor is also set for 600 Ω, the generator dBm reading will be correct. This is also true when driving a 150 Ω load with the internal 150 Ω series resistor selected. Since half the voltage is dropped across the internal resistor and half across the external resistor, the dBu (voltage across the load) output will be 6 dBu down from the output value in dBm for these matching conditions.
Configuring the AM700 Internal series resistor User load resistance Eout Figure 3-14: AM700 generator output voltage divider for dBm calculations Input dBm. This setting defines the external resistance on the input of the AM700 and is used for calculating the input signal amplitude in terms of dBm.
Configuring the AM700 Digital Audio Sampling Rate. In certain situations, the actual sample rate of a digital audio signal can differ from the value contained in the channel status bits. When digital audio is a source of input signals, the frequency measurements of the AM700 can be referred to the actual sample rate or the sample rate obtained from the channel status byte.
Configuring the AM700 Quick Setup One of the configuration choices is the Quick Setup selection. Under this selection is a set of application specific setups that can be used to quickly make the needed instrument configuration changes for an often used measurement setup. Figure 3-16 shows the selection screen with the Audio Analyzer selections; Table 3-1 gives the application-specific choices and the views that the selection produces.
Configuring the AM700 Table 3-1: Quick Setups by Application Application Measurements Views Displayed (Views available but not displayed) FFT Analyzer FFT Analysis FFT1: Channel 1 FFT2: Channel 2 Multitone Level Measurements Meas1: Level Ch1 Meas2: Level Ch2 Meas3: Level Diff Ch1 -> Ch2 Digital Interface Tester View Enables Jitter Spectrum Eye Height Bit Activity Channel Status Audio Analyzer THD and THD+N Meas1: Ch1 THD+N versus Frequency Meas2: Ch2 THD+N vs. Freq. (Meas3: Ch1 THD vs. Freq.
Configuring the AM700 Table 3-1: Quick Setups by Application (Cont.) Application Measurements Views Displayed (Views available but not displayed) Audio Analyzer (cont.) Stereo Differences (Meas1: Ch1 Level vs. Freq.) (Meas2: Ch2 Level vs. Freq.
Applications
Applications This section of the User Manual describes the many audio applications and userselectable features available with the AM700. Audio Generator The AM700 includes both Analog and Digital test signal generators. Each generator can send user-configurable waveforms over two channels or subframes. The analog generator offers two user-selectable modes of operation: high resolution and high bandwidth. In high resolution mode, the generator can produce independent true stereo waveforms.
Audio Generator Signal Postprocessing. A phase offset can be imposed between the digital generator output signals and the digital audio reference input and output. The digital generator can simulate the output signal attenuation effects of long cables. Clock jitter can be added to the output signal to simulate system jitter effects. Subframe Bit Control. The contents of the channel status and user data blocks can be varied independently of the companion subframe. Synchronization.
Audio Generator Control. Press the Control button to display the Generator Control panel shown in Figure 4-2. This is the first of several control panels from which you can configure signal generator characteristics. You can switch between the control panels by touching the soft keys on the left side of the display.
Audio Generator Generator Selection Use the Generator Selection display shown in Figure 4-2 to specify the following generator functions: H Generator type (analog or digital) H Generator mode (high resolution or high bandwidth) H Type of waveform H Digital generator mode (AES or DSP) This display also allows you to assign the front-panel Amplitude and Frequency knobs to a generator and switch generator output on or off.
Audio Generator Follow Mode. Controls are always assigned to at least one generator. They can be assigned to two generators if Follow A is selected and to all generators if both Follow A and Digital Follow Analog choices are selected. An X through an icon shows that the associated generator does not have amplitude and frequency controls assigned to it (see Figure 4-3). Figure 4-3: Amplitude and Frequency control knob assignment selectors NOTE.
Audio Generator Available waveforms include the following: Sine. The most common waveform used in audio analysis. This waveform can be used for testing frequency response, for example, where you measure sine-wave amplitude at various frequencies. The sine wave signal is also the only one that can be swept. Tone Burst. This is a sine wave that is periodically switched on and off.
Audio Generator NOTE. Note: SMPTE and CCIF signal parameters are defined by these organizations. Changing the parameters of the IMD signals from those preset in the AM700 makes the resulting signal noncomplying with SMPTE or CCIF standards. Shaped Noise. This signal can be either white noise or pink noise. White noise contains equal energy across the band, while pink noise contains equal energy per octave. This signal is available from either the analog or digital generator in high resolution mode.
Audio Generator On playback, the contents of the audio source file are copied into a buffer and the generator is set to play the signal from the buffer. The data format is binary 32-bit long words, one long word for each audio sample point. The AM700 uses the lower 24 bits of each word; the upper 8 bits are ignored. Data must be in Motorola fractional audio format (each 24-bit number is expressed as a fraction ranging from 1 to –1, or 7FFFFF to 800000).
Audio Generator Jittered Sine (digital generator in AES mode only). This selection adds a sine wave on the audio and jitters (phase modulates) the digital interface. The frequency (modulating) signal and jitter amplitude can be set in the Waveform Control screen. Measurement units for jitter amplitude are in unit intervals peak-to-peak. One common use for a jittered sine wave is in testing D-to-A converters.
Audio Generator User-specified multitone files can be created and used to set the frequency, amplitude, and phase of the individual tones used to make up the multitone signal. These files must be created externally using an editor that generates ASCII files in DOS format. When constructing a multitone signal there are some rules to make sure the multitone signal will be properly detected by the AM700. Those rules follow the multitone file description. NOTE.
Audio Generator The following explains the format of an AM700 multitone file: where is: am700 multitone is 1.0 is the base 2 log of the buffer size in bytes, that is, 10 for 1024, and so on. consists of a series of lines, each containing . (Each tone is on its own line.) is [] NOTE. The phase parameter is optional.
Audio Generator To select a multitone description file, in the Waveform Control screen, touch the Filename soft key and turn the knob to select the file. Then, touch the Select soft key to accept the selected file. Touch the File soft key to direct the audio generator to the multitone description file as the source for generating multitone signals. Rules for Constructing a Detectable Multitone Signal.
Audio Generator For example, if you want a multitone signal with 10 tones, a record length of 1024, at a sampling rate of 48 kHz, the following constraints on tone selection will apply: Minimum Tone Separation = (48 kHz = 234 Hz 1024) X 5 Minimum Tone Frequency = (48 kHz = 141 Hz 1024) X 3 Maximum Tone Frequency < 24 kHz The two limits that have to be considered in the example are the minimum spacing and the minimum tone frequency.
Audio Generator time required to acquire the record increases a small amount, but you benefit from the improved flexibility in constructing a detectable multitone signal. Enabling Generator Output The Output check boxes are on the right side of the Generator Selection display (see Figure 4-2). Touch an Output check box to switch on or off the output of the selected generator.
Audio Generator Adjusting Generator Frequency and Amplitude You have two ways to adjust generator frequency and amplitude: H From the Generator Status panel on the main display. H From the Waveform Control menu (for appropriate waveforms). From the Generator Status Panel. In the main display, touch the generator icon to display the generator status panel as shown in Figure 4-4.
Audio Generator H The assignment of the Amplitude and Frequency control knobs (shown by the small circular arrow indicators next to the generator and amplitude readouts as shown in Figure 4-5). Amplitude and Frequency knob generator assignment indicators. Figure 4-5: Generator status panel You can coarse adjust the active channel amplitude or frequency by turning the Amplitude or Frequency knob.
Audio Generator If necessary, select the desired waveform from the Waveform pop-up selection. Set the amplitude or frequency by turning the front panel Amplitude or Frequency knob, as appropriate, or activate the field editor by touching it. With the field editor active, you can rotate the large control knob to change the value in the field. You can also enter the desired value in the active window from the keypad. Press Enter or touch the field editor to accept the changes.
Audio Generator Figure 4-6: Waveform control display The amplitude and frequency setting for the selected generator are displayed in the edit fields for Frequency and Amplitude. Values in these fields are parameters of the generator output signal when not sweeping. When sweeping, using the sine wave signal, if one of the sweep parameters is fixed, the amplitude for example, then the value set here for amplitude is the fixed amplitude for the frequency sweep.
Audio Generator Sweep Control The Sweep Control screen allows you to change the sine wave parameters that define the sweep signal for each generator. Use the soft keys at the top of the Sweep Control menu, shown in Figure 4-7, to make the generator selection. When the generators are set to follow, one sweep definition is all that is required, but individual sweep definitions are possible for each generator.
Audio Generator NOTE. When running a voltage sweep, especially with Automatic Timing enabled, the Input Range setting can be set for the highest voltage expected and Auto Range disabled. This eliminates a possible loss of a data point due to the Auto Range action that can occur when the sweep voltage level changes (either up or down). Figure 4-7: Sweep control display Sweep Direction.
Audio Generator Automatic Timing. When auto timing the sweep, the dwell times are calculated and set for the fastest sweep time possible based on the step frequency. Higher frequencies are acquired more quickly than lower frequencies, so dwell times for the high end of the sweep are shorter than those at the low end of the sweep. With Automatic Timing enabled, the number of points can be set, but the dwell and time settings are disabled. Points per Sweep, Point Dwell, and Total Time.
Audio Generator NOTE. To use the list parameters to generate a frequency sweep, you must set Freq Mode to List. To use the list parameters to generate a voltage sweep, you must set Voltage Mode to List. Both must be set to List if you want the voltage and frequency to sweep. If you want to use a fixed voltage level, set the Voltage Mode to Fixed and set the amplitude you want to use in the Waveform Control amplitude editor. List Editor.
Audio Generator The default list has frequencies given in ascending order to match the standard practice of sweeping from the higher frequency to the lower frequency. If you use the Sort by Frequency soft key, the list will be sorted in descending order. You will then have to reverse the sweep direction selection (make it List End to List Begin) if you want to sweep from highest to lowest after using Sort by Frequency.
Audio Generator Advanced Digital Audio Controls in the Advanced Digital Audio screen (see Figure 4-9) include the following: Sample Rate. Touch this soft key and turn the knob to select the audio sampling rate. Signals are calculated with any of the available three sampling rates: 32, 44.1, or 48 kHz. The sample rate selected may or may not change the clock speed of the interface.
Audio Generator Word Size. Use this field editor to specify the number of audio bits that are sent in a digital signal word (the maximum word size that can be sent on an AES interface is 24 bits). Change the word size by touching the Word Size field editor and entering a new value at the keypad. Press the Enter key to accept the entry. After touching the Word Size field editor you can also turn the large knob to display a new value.
Audio Generator User Bits. Touching this soft key displays a menu from which you can select the type of user data produced by the audio generator. Selections are Null (logic 0, the default) or File. No firm standards currently exist that describe uses for the information in user bits. Refer to AES3-1992 (ANSI S4.40-1992) for more information about the user data format.
Audio Generator Data. The data in the example file is: 00000000 10000000 00000000 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 Things to note are: H The data consists of 24 bytes separated by white space. H Line feeds only are used to advance between lines. If a carriage return is used, the file will not be interpreted correctly. H You can describe each byte in decimal, binary, or hexadecimal. The AM700 determines the base by looking at the number of characters you use to describe the byte.
Audio Generator User Bit and Cstatus File Locations. The AM700 expects these files to be in certain directories. Channel status files are placed in the following directories: rom:/cstatus, or nvram:/cstatus User bit files are placed in the following directories: rom:/usrbit, or nvram:/usrbit Users can store files only in the nvram: directory. Filename.
Audio Generator To switch between NVRAM and ROM, touch the Drive soft key. If there is a directory available in the selected drive, the Change Directory soft key can be used to move into that directory if it is selected. To select a directory or file in the list, touch the directory or file name to make the selection. Alternately, the large control knob can be used to scroll through the choice in the list.
Audio Generator Figure 4-11: Advanced Digital Interface display Frequency Mode. Touch this soft key to display a menu containing these selections: Audio Sample Rate, Reference Input, and Variable. The Audio Sample Rate selection sets the base clock frequency for the digital audio and reference outputs to the current audio sample rate (you can specify the audio sample rate in the Advanced Digital Audio screen).
Audio Generator Variable Freq. Edit this field to specify the clock frequency when in Variable Frequency mode. Offset. Edit this field to adjust the output clock signal frequency offset (in parts per million) with respect to the internal audio sample rate or the external reference input. Phase Offset. Edit this field to change the phase (in unit intervals) of the digital audio output clock with respect to the reference output clock. Main Output Interface Amplitude.
Audio Generator Advanced Analog Controls Selections in the top two rows of the Advanced Analog Controls choices, shown in Figure 4-12, apply to Channels A and B separately, while selections in the third row apply to both channels. Figure 4-12: The Advanced Analog Controls display Selections in this screen include the following choices: High Resolution Distortion Reduction. Touch this soft key to toggle between distortion reduction enabled and disabled for both generator channels.
Audio Generator Because this is an analog bandpass filter, time is required to center the filter during a sweep. Disabling Distortion Reduction mode switches the bandpass filter out of the circuit and improves sweep time.
Audio Generator Changing Display Measurement Units in the Status Panel If you want to change display units (for example, to change the displayed frequency units from Hz to kHz or the voltage units from dBu to V) you must first select the editor for the value to be changed by touching it. With the value selected, press the Units front-panel button to display the Units pop-up menu (seen in Figure 4-13). Turn the knob to select the desired units and press the Select key to accept the change.
Audio Generator Set Reference Within the generator status window you can set a generator frequency or level setting to be displayed with reference to a value you specify. This feature can be used, for example, when you want to display the generator output level as a delta from a specified reference value. To set a generator reference, perform the following steps: 1. With an application running, touch the generator status icon to display the generator status window. 2.
Audio Generator 4-36 AM700 Audio Measurement Set User Manual
Audio Analyzer The AM700 Audio Analyzer application provides both graphical displays of audio measurements made on stepped sine-wave signals (either frequency or amplitude sweeps or both) and real-time measurement readouts of the applied signal. Measurements can be made on a single channel, dual channels, and stereo pairs. Available measurements include frequency, level, THD+N, THD, IMD, level difference between channels, phase difference between channels, crosstalk and separation.
Audio Analyzer Acquired audio samples can be processed through one of several standard filters before the measurements are made. Measurements are then made on the filter output and those results are plotted or displayed in the real time measurement readouts. Sweep detection and data settling features assist in defining when acquired data will be accepted and plotted. These features are discussed beginning on page 4-61. Measurement modes available are XY mode and Regulation mode.
Audio Analyzer level difference. Its source can be either Channel 1 or Channel 2. You can plot a dependent variable against the independent variable, which can come from one of the generators. For example, you can plot an acquired level versus a generated level to test response linearity. This allows the linearity test to be performed directly against generator output, eliminating the need to loop the generator back to one of the inputs.
Audio Analyzer Regulation Mode Measurements Like XY measurement mode, Regulation mode can be accessed when you press the Configure button and touch the Measurement Setup soft key. Setting the Measurement mode to Regulation mode displays the choices shown in Figure 4-16. Regulation mode operation is a combined generator and analyzer system for checking the quality of an external device.
Audio Analyzer measured THD as set in the Target Value field editor (the starting and ending frequencies are specified with the Frequency Start and Frequency Stop field editors). See Figure 4-16. Generator and Frequency Selection. In the General Controls menu, you can select the generator to be used (from the Generator selection menu). You can also set the sweep count. A 0 sweep count setting causes a continuous repetitive sweep.
Audio Analyzer Delay Time. Most devices that you might test with Regulation mode do not have instantaneous response time, so you must specify a delay (the amount of time between generator adjustment and first data-point acquisition). Setting a delay is done in the Settled Data Point Detection Controls screen. (See the Settled Data Point Detection Controls discussion on page 4-65.) The suggested minimum delay value for use with Regulation mode measurements is 1.0 to 1.5 seconds. Timeout.
Audio Analyzer Figure 4-17: Regulation mode with Plot Control menu When the selected view is displaying a Regulation mode measurement (as determined by the Measurement mode selection in the Configure Measurement controls shown in Figure 4-16 and the View Setup selection shown in Figure 4-18) the Start Regulation and Stop Regulation soft keys are accessible. (Refer to View Setup on page 3-7 and the View Setup discussion on page 4-74 for more information on setting up a View Type.
Audio Analyzer Figure 4-18: View Setup for Regulation mode measurements Touch the Start Regulation soft key to begin the measurement plot. If you want to stop the measurement before the plot has completed, touch the Stop Regulation soft key. If more than one view is displaying a Regulation mode measurement, as in the example shown in Figure 4-19, touch the view window you want to run Regulation mode in before touching the Start Regulation soft key. Regulation is started in the active view window only.
Audio Analyzer AM700 View 1 Ch A and Ch B Analog Inputs Device under test View 2 A and B Analog Generator Outputs A Generator output level versus freq plot Bandpass of device under test left channel B Generator output level versus freq plot Bandpass of device under test right channel Figure 4-19: Regulation mode bandpass measurement of level versus frequency Making a Closed-Loop XY Measurement There are many parameters that are possible to change when using the Analyzer in closed-loop operation.
Audio Analyzer Some knowledge of the type of information you want to extract from a measurement is required to optimize the generator for your testing application. The example procedure described here uses the Analog generator. The Digital generator can be used for testing digital audio devices. Setting up Meas 1 for a Level versus Frequency measurement is the example used, but the procedure for setting up any of the other available measurements is the same.
Audio Analyzer b. Select Generator as the Sweep Source (this puts the Analyzer in closedloop mode). Notice that all the External Sweep Attributes are grayed out. In closed-loop mode, the Analyzer controls the sweep timing and pressing the Sweep/Run button explicitly determines the start of the sweep. 5. Touch the Settled (Global) choice to display the Settling controls. a. 6.
Audio Analyzer The following procedure describes how to select the generator and waveforms: Generator and Waveform Selection 1. Press the Control button in the Generator section of the front panel to display the Generator Control panel. a. Select the High Resolution generator. Either analog generator can be selected as needed for your test requirement.
Audio Analyzer 3. Touch Sweep Control to display the Sweep Control settings. Notice the message “Sweep timing is being controlled by Analyzer” near the middle of the display area. This confirms that the generator is set for closed-loop operation with the Analyzer. Automatic Timing, Point Dwell, and Total Time are not available choices in closed-loop mode. The Sweep Count setting can be changed. 4. The following choices are made based on the test requirements.
Audio Analyzer b. Set the Impedance to 200 kΩ. The matching requirement for the device being tested is used to determine the setting for your testing application. c. Enable Auto Range. d. Touch the Analog HRes Inputs to quickly set both measurement channels for the High Resolution A/D converters. This can be done individually to make selections for different input sources to the measurement channels (for example, the Analog Generator on Channel 1 and the Digital Generator on Channel 2). NOTE.
Audio Analyzer Related Information Refer to Controlling Plotted Data on 4-58 for directions about how to keep a history of traces for comparison, as shown in Figure 4-20, and to Making Valid Measurements on page 4-52 for directions on enabling the measurements and channels and selecting inputs using the menu choices. These paths are provided in the Analyzer menu to allow quicker access to some of the more often used setup controls without the need to exit the Analyzer screen.
Audio Analyzer Making Valid Measurements The Audio Analyzer application must be configured properly if it is to yield meaningful results. Values generated by Audio Analyzer measurements are not meaningful in all cases. Whether or not a measurement is meaningful depends on the type of input test signal. For example, crosstalk and separation measurements require placing a signal on one channel and monitoring the other (undriven) channel for the presence of audio.
Audio Analyzer Touch the Accept Changes soft key (or the Cancel soft key) to exit the Input Configuration display and return to the application. NOTE. As with most AM700 applications, you can also make an input selection from a subset of the list in the Input Configuration screen by pressing the Menu button (from the main Audio Analyzer display) and touching the Input soft key. Refer to Selecting Input Options below.
Audio Analyzer The Input Select choices allow you to select from analog high-resolution, analog high-bandwidth, or digital input sources. Figure 4-21: Audio Analyzer main menu with Input Range and Input Select submenus The input selections that you make in the Main menu are a subset of the input selections available when you press the Configure button and touch Input Selection.
Audio Analyzer Real Time Readout of Measurements A real time display of the Audio Analyzer measurement readouts can be displayed either separately or together with the graphical displays. The RT View selector toggles the real-time measurements display on and off. Figure 4-22 shows the real-time measurement readouts along with the generator status readout. No graphical displays are shown as none are selected in the Views selection bar.
Audio Analyzer Enabling and Disabling Measurements You can improve the measurement speed of the Analyzer by disabling (shutting off) unneeded measurements. This is especially important when acquiring a fast external sweep. To disable unneeded measurements, press the Menu button to display the Audio Analyzer menus. Touch the Enables soft key to display the Audio Analyzer measurement selections (see Figure 4-23).
Audio Analyzer NOTE. If measurements on either Channel 1 or Channel 2 are not enabled, stereo measurements cannot be enabled. Also, if the Channel 1 and Channel 2 sources are not a stereo pair, stereo measurements are not enabled. For instance, if the Channel 1 source is the High Res generator and the Channel 2 source is the High BW generator, the inputs are not a stereo pair and stereo measurements cannot be made.
Audio Analyzer Controlling Plotted Data Use the selections in the Plot Control screen to control the plotted trace displays (see Figure 4-24). Enable Check the Enable soft key in the Plot controls menu to enable the measurement. History Specify the number of traces to keep for a historical display. Touch the History soft key and enter a value (0 to 4) with the keypad or by turning the control knob. The history setting determines how many previous data traces are displayed.
Audio Analyzer Figure 4-24: Graphical display with Plot Control menu Erase All Plots Erase Current Plot Touch the Erase All Plots soft key to erase the displayed current and all historical plots. Touch the Erase Current Plot soft key to erase the current plot but retain any historical plots.
Audio Analyzer Configuring Measurements Audio Analyzer has up to four graphical views of a measurement and the real-time measurement view. You can display each of these either individually or at the same time if desired. Views can be displayed or dismissed by touching any of the five view selection icons.
Audio Analyzer Regulation mode can be used, for example, to produce a plot of the generator output level versus frequency to yield a constant 1 percent distortion. This capability is typically used by broadcast engineers for proof-of-performance testing. Refer to Regulation Mode Measurements on page 4-40. Sweep Detection Controls The Audio Analyzer works by collecting a series of settled points and assembling them into a trace.
Audio Analyzer Figure 4-25: Sweep detection controls Sweep Detection On. In open-loop operation, the sweep detector determines when one sweep ends and another begins as defined by the External Sweep Attributes and Minimum Sweep Rise/Fall settings. A new sweep is detected when a data point value changes more than the detection level minimum settings (Frequency or Amplitude) in the correct direction (rising or falling) to indicate a sweep start, and a new plot is started.
Audio Analyzer When a frequency sweep is selected the Frequency choice in the Minimum Rise/Fall menu is enabled, and when an amplitude sweep is selected the Amplitude choice in enabled. Minimum Sweep Rise/Fall. Specify the frequency or amplitude rise or fall (as determined by the direction choice in the External Sweep Attributes menu) that must occur to indicate the start of a new sweep. The default minimum rise/fall settings are defined in the instrument specifications.
Audio Analyzer It is possible to set up a different sweep setting for each measurement. If some measurements have more independent variable points specified than others, remember that the sweep does not complete until all the points are taken. As an example, assume measurement 1 is specified as Level versus Frequency in Channel 1 with 16 data points and measurement 2 is enabled and specified as THD+N versus Frequency in channel 2 with 24 data points.
Audio Analyzer Settled data View 1 Delay Meas 1 Delay Idle Start looking for settled data Settling time Settling time Settled data View 1 Generator steps Generator steps Looking for Variance or Delay Looking for Variance or Delay Looking for Variance or Delay Idle Sweep start Settling time Settling time Looking for Variance or Delay Meas 2 Settled data View 2 Settled data View 2 Delay Settling is Global and both measurements wait for the same Delay time to start looking for settled data
Audio Analyzer Touch the Settled soft key in the Configure Measurements Setup screen to display the Settled Data Point Detection Controls (see Figure 4-27). In this display are the controls for defining a settled data point to the Audio Analyzer. You can select the settling mode, the minimum settling level, the amount of delay time for a data sample to settle before it is accepted, and the amount of time to wait for a sample to be acquired.
Audio Analyzer Settling Detector Enable. Checking the Enable Settling Detector causes the Audio Analyzer to use only settled data; leaving it unchecked permits the Audio Analyzer to accept all measurement data from the DSP (digital signal processor). NOTE. Unsettled data points, shown as unfilled circles in a plot, are not considered valid data and are not saved in a history plot if History is enabled in Plot Control. Settling Mode.
Audio Analyzer A flat settling curve applies the Tolerance and Resolution parameters backwards horizontally instead of exponentially and will yield the most accurate settled data points but at the expense of increased settling time. Level Min. You can specify level minimum value. Level values below the specified minimum are not plotted. Delay Time.
Audio Analyzer NOTE. In Regulation mode, continuous rapid plotting of unsettled data points typically means that the settled data criteria are not appropriate. Though it slows data acquisition and display, making the settled data criteria more restrictive and increasing the delay time usually eliminates this behavior. When the correct delay time for a device under test is determined, it should be noted for future testing. Timeout.
Audio Analyzer Resolution. This setting is in units appropriate to the measurement being made. The resolution setting is the absolute difference of a data point value that is considered settled. The default settings for resolution for a measurement are the measurement resolution of the AM700 and can be used in many instances. Tolerance and the Resolution act together across the measurements range.
Audio Analyzer Acquiring a Reference. Set up the Audio Analyzer and make a measurement that provides a trace or single data point to use as a reference. On the front panel, press the Set Ref button to save the acquired data (trace or point) as a reference. On the display status line the AM700 displays a message that a reference trace is available. To acquire a single data point as a reference, sweep detection must be disabled so that a single point can be plotted.
Audio Analyzer Acquire a trace to use dBu 0 Measurement trace –50 Press Set Ref dBu 0 Reference memory trace Set vertical axis to dBr dBr Relative to Ref trace 0 –50 Touch Save To File Touch Load From File Saved reference trace files Figure 4-30: Rel to Ref memory model Naming a Reference File. When designating a file other than the default to save to, touching Filename brings up the Select Reference control screen. This screen displays the directories and file names for selection.
Audio Analyzer Figure 4-31: Relative to Reference setup menu Touch Enter or Done to save the file name and exit the keyboard. Touch Select to exit the Select Reference screen; this selects the file name. You can touch Save to File to store an acquired reference trace to the selected file. The front trace in the active window will be used as the reference trace when there is more than one trace in a view (history traces or dual-trace displays). Load a Ref From a File.
Audio Analyzer NOTE. A reference trace is not displayed for comparison. The plot of new data shows the difference between the reference trace and the new data. To exit the Rel to Ref control screen and save the changes, touch the Accept Changes soft key. View Setup In setting up a measurement view you can select a view type (graphical or table) and select the one of the available measurement traces to display in a view. There are also several option selections for axis scaling and waveform plotting.
Audio Analyzer Input Filtering The AM700 provides several weighting and bandwidth limiting filters. Weighting filters are designed to provide measurements that correlate better with human perception than do unweighted measurements (not only is human ear sensitivity not flat with frequency, but human ear frequency response varies with the amplitude of the sound level). Not all weighting filters are identical. Each filter is an approximation to the sensitivity curve of the ear under certain conditions.
Audio Analyzer Figure 4-32: Filter menu selection with Audio Analyzer 4-76 H Touch the Channel 1 or Channel 2 soft key again to apply the filter selection. H Repeat the selection process for the other channel if desired. H Press the Clear Menu button to accept the filter selection and dismiss the Filter menu. The front-panel Filter button turns the selected filters on or off in both channels.
Audio Analyzer CCIR 468 CCIR ARM A Weighting Figure 4-33: Filter curves: CCIR 468, CCIR ARM, and A Weighting AM700 Audio Measurement Set User Manual 4-77
Audio Analyzer B Weighting C Weighting C Message Figure 4-34: Filter Curves: B Weighting, C Weighting, and C Message 4-78 AM700 Audio Measurement Set User Manual
Audio Analyzer F Weighting 15 kHz, 20 kHz, and 22 kHz Low Pass 400 Hz High Pass Figure 4-35: Filter Curves: F Weighting, 15 kHz, 20 kHz, and 22 kHz Low Pass, and 400 Hz High Pass AM700 Audio Measurement Set User Manual 4-79
Audio Analyzer Cursors Cursors can be used to select measurement points in a waveform. Cursor position is adjusted using the Control Knob with cursor positioning active. The cursors can be used to provide a continuous readout of the amplitude and frequency at the cursor position. Pressing the Cursors button places two cursors on the display and lets you position them to mark display features.
FFT Analyzer An audio signal is composed of many frequency components. Some of these components can be due to undesirable effects of harmonic distortion or noise. Using an oscilloscope to view the signal waveshape in the time domain does not permit these unwanted frequency components to be distinguished from the desired audio signal. The FFT Analyzer breaks the signal apart into its various frequency components.
FFT Analyzer Measurement Bandwidth The FFT Analyzer has two measurement bandwidths. The high resolution mode provides a useable bandwidth of DC to 20 kHz, and the high bandwidth mode provides a useable bandwidth of DC to 80 kHz. Displayed data can be acquired over a changing span of 400 Hz to 80 kHz. Windowing Weighting functions are applied to the sampled window to reduce the effects of out-of-window spectral components.
FFT Analyzer Figure 4-37: FFT Analyzer Window menu display Kaiser-Bessel. The K-B window produces improved side-lobe attenuation resolution at the base and is similar to BH4 window for frequency resolution. It is very useful for looking for frequency components closer to the noise floor. BH4 (Blackman-Harris). The BH4 window provides very good frequency resolution at the bin frequency but has less side-lobe attenuation. Saramaki Rajan. This is a Tektronix-developed window similar to Kaiser-Bessel.
FFT Analyzer Uniform (no window) Best selectivity if the signal frequency is exactly equal to a frequency bin, poor resolution of adjacent frequencies, poor amplitude accuracy. Used to look for transients that do not fill the entire record. Hann Most used compromise; good selectivity, good resolution, good amplitude accuracy. Flat-top Used for best amplitude accuracy; adjacent frequency resolution poorer. Kaiser-Bessel Best resolution at base, fair resolution at center, fair amplitude accuracy.
FFT Analyzer am700 window 1.0 0.01 0.015 0.020 etc. for 513 numbers separated by white space. Spaces, tabs, and Carriage return/line feed are considered blank space. The file consists of the header that defines the file as a window file for the AM700 version 1.0 followed by 513 floating point numbers, in ASCII format, that define the weighting factor to be applied to the frequency bins. The numbers can be entered in either exponential or decimal form (1.2e–2 or 0.012, for example).
FFT Analyzer Spectrogram. This is a display of time versus frequency versus amplitude. Amplitude is color coded in the AM700 display and in the VGA output to an external monitor. A comparison of the Bar Graph and Spectrogram display is shown in Figure 4-39.
FFT Analyzer Contrast is adjustable using the scaling on the vertical axis of the Spectrogram display. Select the y-axis and rotate the control knob to adjust the contrast of the display or press the front-panel Rescale button. Horizontal expansion in the x-axis of the display can be used to closely examine the area around one of the spectral components. In Multitone mode the choices are Point Plot and Table display. Point Plot.
FFT Analyzer Figure 4-40: FFT Input Select and Input Range menus Cursors Cursors can be used to select measurement points in a waveform. Cursor position is adjusted using the control knob with cursor positioning active. The cursors can be used to provide a continuous readout of the amplitude and frequency at the cursor position. Pressing the Cursors button places two cursors on the display and lets you position them to mark display features.
FFT Analyzer Averaging Averaging is available for the FFT Analyzer displays. Pressing the Average button lights the label on the front panel and enables the selected type of averaging (noise reduction) on the displayed signal (if Averaging is applicable). Pressing and holding the Average button displays the Average menu. In that menu you can set the number of averages (up to 9,999) and specify whether averaging is based on minimum, maximum, or average signal values.
FFT Analyzer Figure 4-41: Zoomed FFT display showing maximum expansion of the trace Multitone Measurement Mode Most audio tests consist of measuring a sine-wave audio tone, then stepping the frequency and repeating the test. The process continues until measured level versus frequency graphs can be assembled and displayed. Each audio test typically takes several seconds. The technique is accurate, and when time is not an issue, is the best way to perform an audio test.
FFT Analyzer waves at several frequencies. From the received multitone signal, Multitone measurements produce level versus frequency or distortion plus noise graphs. Multitone detection and measurements are made using FFT techniques. In order to correctly detect and analyze multitone signals the FFT size should be greater than or equal to the record size used for generating multitone signals.
FFT Analyzer The files of multitones that are included in the rom:/mtone directory are those generated by the Tektronix ASG100 Audio Signal Generator. You can add more multitone descriptions to the nvram:/mtone directory by creating a file that has the description of the input multitone signal. Multitone files are described in the Audio Generator information on page 4-9. NOTE. When setting up to use multitone test signals, the generator and the multitone detection must be set to the same multitone signal.
FFT Analyzer Figure 4-43: Multitone measurement settings in the Configure Measurements menu These measurement selections must be made in the Measurement Setup choices of the Configure menu. Selection choices for the measurement trace or traces to be displayed in View 1, View 2, View 3, or View 4 are those that have been set up in the Measurement column when the View Setup menu is displayed (see Figure 4-44).
FFT Analyzer Figure 4-44: FFT View Setup A typical multitone graphical display showing a two-view display is seen is Figure 4-45. A comparison between the FFT display of the multitone signal and the corresponding multitone measurement is shown in Figure 4-46. The table display is shown in Figure 4-47.
FFT Analyzer Figure 4-45: Multitone Analyzer display with two measurement windows Figure 4-46: Display of FFT multitone signal and the corresponding multitone measurement AM700 Audio Measurement Set User Manual 4-95
FFT Analyzer Figure 4-47: FFT multitone table display NOTE. The amplitude of an individual tone in a multitone signal is not the amplitude that is set for the overall multitone signal. The overall multitone signal level is the RMS value of all the tones combined to produce the multitone signal.
Audio Monitor You can use the Audio Monitor application to make time-domain measurements of signal amplitude on an audio signal and verify that audio signals are present. At the 48 kHz sampling rate of high resolution mode, the record is a little over 1 second in length, the sample buffer being 51,200 bytes in length. The record time varies with the sample rate. The sample rate in high bandwidth mode is 192 kHz, and the digital fixed sampling rates are 32, 44.1, and 48 kHz.
Audio Monitor Displays Audio Monitor provides a one- or two-channel view of signal amplitude versus time. At application startup, the scale factors are set for 0.7 V peak-to-peak and 0.5 seconds. Press the Rescale button to scale the view to the applied signal. The display is similar to that of a digitizing oscilloscope with a touch-and-zoom user interface for sizing and positioning the displayed waveform.
Audio Monitor View Setup To configure Audio Monitor views, touch the Setup icon to display the View Setup screen, then select the desired views, measurements, view types, and view options. Touch Accept Changes (or Cancel) to exit the view setup screen and return to the Audio Monitor display. The View Setup screen and its selections are shown in Figure 4-50. Figure 4-50: The View Setup screen for Audio Monitor View Types. Only Interpolator View Type is supported for the Audio Monitor.
Audio Monitor From the View Setup screen displayed when you touch the Setup icon (see Figure 4-50) you can configure up to four views of the two input channels. For example, Channels 1 and 2 can be displayed separately or overlaid in the same view, as shown in Figure 4-48 and Figure 4-49. When you overlay them in the same view, traces are distinguished by color. A channel label of the same color on the trace near the graticule identifies each displayed channel.
Audio Monitor Saving Changes and Exiting View Setup Menu. At the bottom of the control panel are the choices for accepting and saving any changes you may have made or cancelling the changes made. Accept Changes and Cancel both exit back to the application window. Pressing Clear Menu also exits back to the application and cancels any changes that were made as does the Cancel selection.
Audio Monitor Figure 4-52: Use of Cursors to measure pulse time Pressing the Cursors button places two cursors on the display and lets you position them to mark display features. The numerical display shows frequency and level at each cursor location and the timing difference between the two cursors. Refer to Cursors on page 2-10 for more details on cursor operation.
Audio Monitor Menu Pressing the Menu button displays the Audio Monitor selections and corresponding submenus. The main menu selections are Input and Trigger. Figure 4-53: Input selections in Audio Monitor menu Input Select The Input submenu, shown in Figure 4-53, contains the selections for input range and types exactly as seen in the other applications.
Audio Monitor The Input Select submenu also allows you to select input source: Analog High Resolution, Analog High Bandwidth, or Digital Main. When Digital Main is selected, applied digital signals are decoded and displayed as an analog audio signal. Trigger Selects The Trigger submenu shown in Figure 4-54 contains the selections for setting up trigger conditions and enabling the trigger. This menu displays the trigger controls. Figure 4-54: Triggering selections in Audio Monitor menu Trigger Source.
Audio Monitor External trigger can be used to determine the phase difference relationship between two signals that are both related to a common trigger, but are not a stereo pair. Trigger Mode. Trigger mode can be Auto or Normal. In Normal mode the trace is displayed only when trigger level and slope conditions are satisfied. In Auto mode the trace is displayed either when trigger conditions are satisfied or when a predetermined timeout occurs. Trigger Slope.
Audio Monitor 4-106 AM700 Audio Measurement Set User Manual
Digital Interface Tester Use the Digital Interface Tester application to make extensive evaluations of the electrical and data characteristics of industry standard digital audio interfaces including AES/EBU, SPDIF (also known as consumer), and optical consumer. Serial Data. The Digital Interface Tester is used to check the bit stream output of serial digital devices to look for bit settings, checking the number of bits, and comparing subframe data bits for differences.
Digital Interface Tester Eye Diagram Display. Use the Eye Diagram display to present a straightforward indication of the condition of a digital audio interface. Jitter, rise time, and interfering signal problems are all quite apparent in the Eye Diagram format. Digital Jitter. Jitter can be present on the interface signal.
Digital Interface Tester Figure 4-56: Digital Interface Tester Input Configuration menu No Signal. When there is no digital signal applied, or the applied signal deteriorates to the point that the AM700 can no longer lock on, there some indicators that supply visual feedback as to what is occurring. In the absence of a signal, “No input” is displayed immediately below the measurement name in the view window or, in the case of the Bit Activity display, across the graticule display.
Digital Interface Tester View Setup Make the choices for View Types and View Options in this menu. Choices made in either View Types or View Options apply only to the view selected in the top View Selection bar (View 1, View 2, View 3, and View 4). A small icon in the View Selection choice shows the current View Option in effect for the associated view. The meaning of the View Type icons appears in the label in the View Setup control screen.
Digital Interface Tester View Selection Bar Across the top of the Digital Interface Tester you see the view selection bar as shown in Figure 4-58. It has active soft keys that are used to select the view window to be displayed and to permit making View Option choices. The default selection is a display of view 1 with Bit Activity selected. Other views can be selected or they can all be hidden using the soft keys.
Digital Interface Tester Bit Probability Display View the bit activity for the serial digital frames using the Bit Probability display seen in Figure 4-59. When the digital generator is connected to the digital input, the C and P bits always have activity even if the generator output is off or if the generator output is on and the digital channels are disabled. When a digital audio signal is applied, the active bits of the digital word are displayed.
Digital Interface Tester Channel Status Display View the bit values (ones and zeros) of the digital signal information in a byteby-byte table showing the byte number and value contained in the bytes (see Figure 4-60). Both subframe 1 and subframe 2 are displayed in the table for comparison. The display for views can be altered by selections available in the View Setup menu as shown in Figure 4-61.
Digital Interface Tester X/Z and Y Subframes. X/Z is digital subframe 1 and Y is digital subframe 2 from the generator. Select either subframe to be displayed by itself or choose to show the differences between the two subframes. Differences are indicated by underlining the bits that differ. Other options are to show the data in hexadecimal format, show the data in the order of transmission, or to display the decoded data in tabular format as seen in Figure 4-62.
Digital Interface Tester Professional grade Consumer grade Figure 4-62: Decoded channel-status data display AM700 Audio Measurement Set User Manual 4-115
Digital Interface Tester Eye Diagram Display Use the eye diagram display seen in Figure 4-63 is to view binary-coded digital signals to see the voltage levels used to represent the two logic states and the transitions between them. Proper distance between the logic levels, as well as proper position of the transitions, is important for error-free data transmission.
Digital Interface Tester sufficient for the receiver to clearly detect whether a high or a low logic level occurs. This separation is the eye opening of the signals, so called because of it eye-shaped pattern. Above the eye diagram display is a real-time readout area showing measured parameters of the digital signal.
Digital Interface Tester Long cable simulator only Long cable simulator with jitter added Figure 4-64: Eye Diagram with jitter and long cable effects simulated with the Long Cable simulator 4-118 AM700 Audio Measurement Set User Manual
Digital Interface Tester Digital Jitter Measurement If several pieces of equipment are cascaded, jitter may accumulate. An input interface at the end of the chain will be required to correctly decode a signal with much more jitter than each earlier stage would produce when operating alone. There are many experiences of end users coming across problems related to this jitter build-up. These problems can occur despite all the equipment involved apparently conforming fully to the present interface standards.
Digital Interface Tester Figure 4-66: Jitter View Types Jitter Spectrum View Types 4-120 As with the FFT Analyzer, the jitter spectrum display may be as the point-to-point plot of the Interpolator, as a Bar Graph display, and as a Spectrogram as shown in Figure 4-66. The Bar Graph and Spectrogram displays are compared in Figure 4-67 on page 4-121.
Digital Interface Tester Bar graph display of jitter spectrum Spectrogram display of jitter spectrum Figure 4-67: Comparison of Bar Graph and Spectrogram displays of a jitter spectrum AM700 Audio Measurement Set User Manual 4-121
Digital Interface Tester Digital Interface Tester Main Menu The Digital Interface Tester menu selections provide unique functionality to the application. The main menu bar, as shown in Figure 4-68, has five soft keys that show additional submenu choices. You may also access many of these choices for setting digital generator parameters through the Advanced Digital Interface and Advanced Digital Audio soft keys found in the Generator Control panel.
Digital Interface Tester Sample Rate. Configures the output sample rate for the audio created by the digital generator. Choices are 48 kHz, 44.1 kHz, and 32 kHz. Word Size. Allows you to configure the number of bits used in each audio sample. The allowable range is 8 to 24 bits. Dither Type. Use this choice to configure the type of dither. Options are None, Rectangular, and Triangular.
Digital Interface Tester BNC Output. Specifies the output voltage of the digital BNC connector. This is constrained to always be five times smaller than the XLR output voltage. Adjusting this field also adjusts the XLR output voltage. Range of the BNC output is 0.00 V to 2.05 V (one-fifth of the XLR output). Jitter Generation These selections are used to control the generator. The choices are sine wave, jittered sine wave, jitter amplitude, and jitter frequency.
Digital Interface Tester Eye/Jitter Detection The menu choices here control the low frequency jitter rejection bandwidth, the jitter gain, and the equalization feature. LF Rejection - 120 Hz. When selected, filters out jitter below 120 Hz. LF Rejection - 1200 Hz. When selected, filters out jitter below 1200 Hz. This filter attenuates the lower frequency jitter components and is used when those components are excessive. Jitter Gain. Toggles between X1 gain and X8 gain only in jitter spectrum mode.
Digital Interface Tester Table 4-1: Subframe Time Slots Time Slots Information Carried 0 to 3 One of the three permitted preambles (X, Y, or Z) 4 to 27 Audio sample word in linear twos complement. The most-significant bit (MSB) is in time slot 27. When a 20-bit coding range is enough to carry the audio signal representation, time slots 8 to 27 are used for that purpose with the LSB in time slot 8. Time slots 4 to 7 (auxiliary bits) can then be coded to carry different data.
Digital Interface Tester Digital Interface Terminology Sampling frequency Frequency of the audio signal samples. If more than one audio signal is transmitted through the same interface, the signal samples are at the same frequency. Audio sample word Digital audio signal amplitude. Representation is linear in a twos complement binary form. Positive numbers correspond to positive analog voltages at the input of the analog-to-digital converter (ADC).
Digital Interface Tester 4-128 Block A block is 192 consecutive frames in a group. Channel coding Coding describes how transmitted binary digits are represented. Jitter Intrinsic clock generator phase noise, timing error amplification due to poor phase-locked-loop damping, and pattern-dependent logic edge changes induced by high-frequency loss down long cables.
Function Operation AM700 functions are user-defined sequences of commands. Functions can be written in SCPI command protocol for downloading to the AM700. The Function key provides a user interface for execution of stored functions (see Figure 4-70). Figure 4-70: Function control menu Function Control You can create a function externally and load it through the GPIB interface or the floppy disk drive as an executable file of SCPI commands.
Function Operation Running a Function Functions are stored in two different directories in the AM700. Those stored in rom:/function are permanently stored for specific purposes by the factory. Those stored in nvram:/function are user generated. From the front panel, stored functions can be started using menu choices called up by the Function button. 1. Press the Function button to bring up the menu of available functions. 2.
Function Operation H If double quote marks are used in a SCPI command, they must be escaped by a backslash (\“string\”) in order to pass them to SCPI using the Tcl scpi command. H Precede all SCPI commands with the string “scpi”. The Tcl parser looks first to see if it is a Tcl command that it knows about; if so, it runs it as a Tcl command. If not, the parser looks for *, ?, or : in the command lines to see if it is a SCPI command.
Function Operation #Start the Audio Monitor application scpi INST:SEL MONITOR #Display two measurement windows; view 1 is displayed by default. scpi DISP:WIND2:STAT ON #The Function Control Panel remains displayed unless it is #cleared by the front panel control.
Function Operation Figure 4-71: Storage Manager control screen Copying a File. Copying a file from a floppy disk into the nvram function file is also done using the Storage Manager control screen also shown in Figure 4-71. 1. Touch Drive on the right side of the Storage Manager screen to select the nvram:. 2. On the right side of the Storage Manager screen select the function directory. This done by first touching the directory name to shift the knob focus to that side.
Function Operation 5. Touch Drive on the left side of the Storage Manager to select dos:. A list of the directories and files at the top level of the disk directory will be displayed. 6. Touch a file name in the files display area to shift the knob focus to the left side, and use the large control knob to select the file to be transferred. 7. Touch Copy to transfer the file from dos: to nvram:/function.
Function Operation A cron_string is five fields consisting of the following: MIN HOUR DAY_of_MONTH MONTH DAY_of_WEEK The numerical ranges for the fields are as follows: H Minutes: 0 through 59. H Hours: 0 through 23. H Day of the month: 1 through 31. H Month: 1 through 12. H Day of the week 0 through 6; Sunday is day 0. Each field can contain any of the following type entries: a single number, a comma-separated list of numbers, a hyphen-separated pair of numbers, or an *.
Function Operation PROG:EXPL commands are used in the same manner as the PROG:SEL commands but explicitly name the function to which the command applies. Refer to the AM700 Programmers Manual for further details on the PROGram commands and their use in running functions. PROG:EXPL:TIM , Example: Using the SCPI commands requires the following steps: Save AM700 State Function 1. Send PROG:CAT? to get a comma-separated list of the available functions.
Function Operation The AM700 State Save function saves the following settings: H Application settings H Generator settings H Input settings H COM port and GPIB settings H Printer settings (except printer destination) It does not save the following settings: H Relative-to-reference information H Regulation mode settings H DSP generator settings AM700 Audio Measurement Set User Manual 4-137
Function Operation 4-138 AM700 Audio Measurement Set User Manual
Appendices
Appendix A: Specifications The performance limits in this specification are valid with the following conditions: H This instrument must have been calibrated/adjusted at an ambient temperature between +20° C and +30° C. H The instrument must be in an environment with temperature, altitude, humidity, and vibration within the operating limits described in Table A-14 on page A-29. H The instrument must have had a warm-up period of at least 20 minutes.
Appendix A: Specifications Table A-1: Analog Analyzer Specifications (Cont.) Capabilities Description Input Characteristics Full Scale Input Ranges From –22 dBu (62.5 mVRMS) to +44 dBu (125 VRMS) in 12 6-dB steps Input gain ranges are in 6 dB steps from –22 dBu to +8 dBu and in 12 dB attenuator steps (with intermediate 6 dB gain steps) from +8 dBu to +44 dBu. Autoranging may be selected to switch the gain appropriately on the level of the input signal.
Appendix A: Specifications Table A-1: Analog Analyzer Specifications (Cont.) Capabilities Description Input Characteristics Crosstalk +Noise, Channel-to-Channel This is a wideband measurement of the level difference between the undriven channel and the driven channel. Driven channel input is a +8 dBu sine wave. Undriven input terminated in 600 Ω.
Appendix A: Specifications Table A-1: Analog Analyzer Specifications (Cont.) Capabilities Description Input Characteristics Channel Separation (High Resolution Mode) This is a measurement of the level of the driven channel with respect to the undriven channel with a bandpass filter centered on the driven channel frequency. The measurement is primarily noiselimited; therefore, measured values improve as input amplitude increases.
Appendix A: Specifications Table A-1: Analog Analyzer Specifications (Cont.) Capabilities Description Input Characteristics Undriven Channel Set to Autorange (driven input = +8 dBu on +8 dBu input range) CH A into CH B 70 Hz to 5 kHz w115 dB u5 kHz to 40 kHz w105 dB u40 kHz to 80 kHz w 95 dB CH B into CH A 70 Hz to 5 kHz w112 dB u5 kHz to 40 kHz w110 dB u40 kHz to 80 kHz w108 dB Amplitude Measurement Amplitude Accuracy at CAL Frequency +8 dBu FS 0.1 dB at 120 Hz Other gain steps FS 0.
Appendix A: Specifications Table A-1: Analog Analyzer Specifications (Cont.) Capabilities Description Amplitude Measurement Amplitude Accuracy (relative to Accuracy at CAL Frequency) (High Bandwidth Mode) 10 Hz to 20 kHz 20 to 70 kHz 70 to 80 kHz Inputs >1 mV (–57.8 dBu) to 10 mV (–37.8 dBu) 1.0 dB 1.0 dB 2.0 dB Input > 10 mV (–37.8 dBu) to 1.946 V (+8 dBu) 0.15 dB 0.2 dB 1.0 dB 0.25 dB 1.0 dB (Typically 0.05 dB from 50 Hz to10 kHz) Input > 1.
Appendix A: Specifications Table A-1: Analog Analyzer Specifications (Cont.) Capabilities Description Amplitude Measurement High Bandwidth Mode At +8 dBu FS At other gain steps FS 62.5 mV (–22 dBu) 10 Hz to 20 kHz 20 to 70 kHz 0.2 dB (typically 0.35 dB 0.05 dB from 50 Hz to 10 kHz 0.25 dB 0.35 dB 70 to 80 kHz 1.0 dB 1.0 dB The accuracy of the measurement may be noiselimited for amplitudes below 62.5 mV (–22 dBu).
Appendix A: Specifications Table A-1: Analog Analyzer Specifications (Cont.) Capabilities Description THD + N Measurement High Bandwidth Mode Residual THD + N THD + N measured using the high bandwidth ADC over an 80 kHz BW. The measurement is noiselimited for amplitudes below 125 mV (–16 dBu). Input > 125 mV (–16 dBu); frequency v20 kHz to w72 Hz. Typically v0.03% , maximum 0.05%. High Resolution Mode Residual THD + N Measurement bandwidth = 20 kHz Input Amplitude > 62.5 mV ([–21.9 dBu) v0.
Appendix A: Specifications Table A-1: Analog Analyzer Specifications (Cont.) Capabilities Description THD + N Measurement High Resolution Mode Residual THD + N (cont.) On –4 dBu Input Range At Full Scale At Full Scale –6 dB 0.003% 0.006% 0.0075% 0.006% 0.0125% 0.0075% 400 Hz to 6.6 kHz 0.005% 0.010% 100 Hz to 400 Hz 0.0075% 0.010% 20 Hz to 100 Hz 0.015% 0.011% 400 Hz to 6.
Appendix A: Specifications Table A-2: Electronic Triggers Specifications Capabilities Description Trigger Input Number of Trigger Inputs One input located on the rear panel. Electrical Characteristics TTL-level, Schmitt-trigger input Connector Type BNC female Psuedo Triggers Trigger Events Two trigger events may be generated by remote control using the commands in the SCPI TRIGger subsystem: STARt starts the sweep running and STOP ends the sweep.
Appendix A: Specifications Table A-3: Analog Generator Specifications (Cont.) Capabilities Description Output Characteristics Channel Separation High Resolution Mode 100 dB for frequencies 20 Hz High Bandwidth Mode 70 dB for frequencies 70 Hz Signals and Control All signals are generated digitally using software running on a DSP56002 digital-signal processor, driving audio digital-to-analog converters. Types of Signals Supported by Hardware Signals that are band limited to 80 kHz.
Appendix A: Specifications Table A-3: Analog Generator Specifications (Cont.) Capabilities Description Amplitude Related Characteristics Full Scale Output Amplitude Ranges (Balanced outputs with source R = 10 Ω nominal) Measured into a high impedance load. Amplitudes will be approximately 0.14 dB lower if measured across a 600 Ω load when the source R = 10 Ω nominal. Every 6 dB from –22.1 dBu (60.8 mVRMS) to +13.9 dBu (3.84 VRMS) plus +20 dBu (7.75 VRMS), +26.0 dBu (15.45 VRMS), and +30 dBu (24.
Appendix A: Specifications Table A-3: Analog Generator Specifications (Cont.) Capabilities Description Amplitude Related Characteristics Amplitude Flatness, High Resolution Generator Relative to 120 Hz Levels from –22.1 dBu to +30 dBu Normal Mode 10 Hz to 10 kHz u10 kHz to 20 kHz 0.1 dB +0.1 / –0.2 dB Low Distortion Mode 10 Hz to 1 kHz u1 kHz to 10 kHz Amplitude Flatness, High Bandwidth Generator Relative to 120 Hz 11.7 Hz to 20 kHz u20 kHz to t70 kHz 70 kHz u70 kHz to t80 kHz 80 kHz +0.1 / –0.
Appendix A: Specifications Table A-3: Analog Generator Specifications (Cont.) Capabilities Description Amplitude Related Characteristics Interchannel Amplitude Flatness Relative to 120 Hz Levels from –22.1 dBu to +30 dBu High Resolution Generator Normal Mode 10 Hz to 10 kHz u10 kHz to 20 kHz 0.2 dB 0.4 dB Low Distortion Mode 10 Hz to 1 kHz u1 kHz to 10 kHz 0.5 dB 1.0 dB High Bandwidth Generator 11.7 Hz to 20 kHz u20 kHz to 70 kHz u70 kHz to 80 kHz 0.2 dB 1.0 dB 1.
Appendix A: Specifications Table A-3: Analog Generator Specifications (Cont.) Capabilities Description THD + N Residual THD + N (Low Distortion Mode ) Residual THD+N with the bandpass filter in place. These specifications are baseline for sine waves generated in the low-distortion mode. Load resistance w 600 Ω Over 22 kHz BW 100 Hz to 749 Hz Amplitudes w+4 dBu to v+26 dBu 20 Hz to 749 Hz Amplitudes w+8 dBu Amplitudes w0 dBu Amplitudes w–4 dBu Amplitudes w–10 dBu Amplitudes w–16 dBu 750 Hz to 7.
Appendix A: Specifications Table A-4: Digital Audio Unit Specifications Capabilities Description The Digital Audio Unit includes a generator, a reference generator, a main receiver, and a reference receiver. These four sections can operate simultaneously, each at its own sample rate. Interface Characteristics The generator always drives the Digital Out XLR, Unbalanced Out BNC, and Optical Out connectors.
Appendix A: Specifications Table A-4: Digital Audio Unit Specifications (Cont.) Capabilities Description Input and Output Levels AES/EBU I/O Levels Input levels required for normal operation and the output levels available. For details on measured or programmable parameters, see either Main Receiver Interface Parameter Measurements or Generator Variable Parameters. Digital In 0.15 V to 10 V peak-to-peak Unbalanced In 30 mV to 2 V peak-to-peak Digital Reference In 0.
Appendix A: Specifications Table A-4: Digital Audio Unit Specifications (Cont.) Capabilities Description Receiver Interface Parameter Measurements Clock Rate Range All inputs: 30 kHz to 52 kHz Accuracy 10 ppm Input Equalization The Main Input includes automatic line equalization to measure and correct roll-off due to typical 110 Ω digital audio cable.
Appendix A: Specifications Table A-4: Digital Audio Unit Specifications (Cont.) Capabilities Description Receiver Interface Parameter Measurements Eye Diagram Peak-to-Peak Jitter Range 0 to 0.8 UI peak-to-peak jitter Accuracy LF Reject = 120 Hz (response falls 6 dB per octave below about 100 Hz) (0.02 UI + 5%) for sinusoidal jitter above 500 Hz LF Reject = 1200 Hz (response falls 6 dB per octave below about 1000 Hz) (0.
Appendix A: Specifications Table A-4: Digital Audio Unit Specifications (Cont.) Capabilities Description Reference Input Parameter Measurements Clock Rate Range 30 kHz to 52 kHz Accuracy 10 ppm Generator Variable Parameters Clock Rate Range All Inputs and Outputs 30 kHz to 52 kHz Clock Rate Accuracy The primary clock rates (32, 44.1, and 48 kHz) are synthesized exactly, so accuracy depends solely on the accuracy of the reference used (internal or external).
Appendix A: Specifications Table A-4: Digital Audio Unit Specifications (Cont.) Capabilities Description Generator Variable Parameters Cable Simulator Simulated Cable Response A selectable cable simulator inserts the response of a long, typical digital audio cable in the frontpanel Digital Out signal. 125 ns to 175 ns rise time measured at the second transition of the preamble of subframe 1 Output Level Range XLR: 0 to 8.0 V p-p into 110 Ω BNC: 0 to 2.
Appendix A: Specifications Table A-4: Digital Audio Unit Specifications (Cont.) Capabilities Description Reference Output Variable Parameters Clock Rate Accuracy Same as Internal clock rate accuracy. Reference Output Residual Jitter Clock Source From Audio Frequency Offset = 0 Frequency Offset < > 0 or Clock Source is Variable Clock Source From Reference (external reference is required) A-22 0.03 UI p-p maximum 0.08 UI p-p maximum (0.
Appendix A: Specifications Table A-5: Display System Capabilities Description Display Display Type Color LCD flat panel; backlighted Display Size 6.4 inches (162.6 mm) diagonal Display Resolution 640 (H) X 480 (V) pixels (VGA) Touch Panel Description Analog resistive touch screen Size Width 6.615 inches (168 mm) Height 5.33 inches (135.4 mm) VGA Output Resolution 640 X 480 VGA Signal Levels Level Voltage White Level 0.
Appendix A: Specifications Table A-5: Display System (Cont.) Capabilities Description VGA Output Timing Pin Out Signal Time/Frequency Dot Clock Horizontal Rate Vertical Rate 25.175 MHz 31.469 kHz 59.940 Hz Pin Number 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 Description Red Green Blue NC Ground Red Ground Green Ground Blue Ground NC Ground NC NC Horizontal Sync Vertical Sync NC Table A-6: Software Update Procedure Capabilities Description Update Procedure AM700 firmware may be updated from a 1.
Appendix A: Specifications Table A-7: Nonvolatile Memory Capabilities Description Battery-backed SRAM Storage Capacity 1 Mbyte Retention Time (the length of time that stored waveforms and setups are retained without power to the instrument) Internal batteries, installed at the time of manufacture, have a life of greater than 10 years when operated and stored at an ambient temperature from 0_ C to 50_ C. Retention time of the nonvolatile memories is equal to the remaining life of the batteries.
Appendix A: Specifications Table A-9: Front Panel Hardware Capabilities Description Audio Input and Output Connectors Analog Audio Standard XLR female: pin 1 shield, pin 2 +, pin 3 – Digital Audio Input: XLR female, Output: XLR male Headphone Jack Standard 1/4 inch, stereo Channel A is left; Channel B is right.
Appendix A: Specifications Table A-10: Rear Panel Hardware (Cont.) Capabilities Description COM1 and COM2 Connectors DB9 male, configured as RS–232C, DTE; provides connection for serial printers.
Appendix A: Specifications Table A-12: Safety Standards Category Standards U.S. Nationally Recognized Testing Laboratory Listing ANSI/ISA S8201 – Safety Standard for Electrical and Electronic Test, Measuring, Controlling, and Related Equipment, 1994 Canadian Certification CAN/CSA C22.2 No. 1010.
Appendix A: Specifications Table A-14: Environmental Characteristics Capabilities Description Atmospherics Temperature Operating –10_ C to +50_ C, Class 5 Nonoperating (storage) –51_ C to +71_ C. Class 3 Humidity To 95% relative humidity at or below +55_ C.
Appendix A: Specifications Table A-15: Dynamic Characteristics (Cont.) Capabilities Description Shock Loose Load Vibration 1 inch p-p sinusoidal at approximately 4.5 Hz with at least 1/16 inch peak separation between the packaged product and the surface. Thirty minutes in normal shipping orientation, 30 minutes split between other possible shipping orientations. Vehicle Vibration 1.33 gRMS, random vibration, from 5 to 500 Hz, 60 minutes on each axis.
Appendix A: Specifications Table A-16: Electromagnetic Compatibility Capabilities Description EMC Requirements Emissions Emissions are be within the limits specified by the following requirements. Enclosure EN55022 Class B limits for radiated emissions AC Mains EN55022 Class B limits for conducted emissions To ensure compliance with the above requirements, only high-quality shielded interface cable should be attached to this instrument.
Appendix A: Specifications Table A-16: Electromagnetic Compatibility (Cont.) Capabilities Description EMC Requirements Immunity, Fast Transients, Common Mode IEC 801-4 1988 No loss of stored data, change to control settings, or temporary loss of function will occur when the instrument is subjected to transients as described below. FCC Port Peak (kV) Tr/Th (ns) Rep Frequency (kHz) Signal & Control 0.5 5/50 5 DC Power 0.5 5/50 5 AC Power 1.
Appendix A: Specifications Table A-17: Mechanical Characteristics Capabilities Description Standard Instrument Weight (nominal) Instrument by Itself 32.25 lbs (14.66 kg) With Front Cover and Accessories 34 lbs (15.45 kg) Domestic Shipping Weight (with shipping box, including instrument, manuals, foam, and snap-on cover. Optional service manual not included.) 45 lbs (20.454 kg) Shipping Box Length 28 in (711.2 mm) Width 23 in (584.2 mm) Height 19.5 in (495.3 mm) Volume 7.3 cubic feet (0.
Appendix A: Specifications Table A-17: Mechanical Characteristics (Cont.) Capabilities Description Rackmounted Instrument Weight of Rackmounted Instrument, and the Rackmount Conversion Kit The swing handle of the AM700 must be removed to mount it in the rackmount adapter. Kit Weight 3.5 lbs (1.6 kg) Domestic Shipping Weight 6 lbs (2.73 kg) Weight of Rackmounted Instrument 30 lbs (13.64 kg) plus the weight of rackmount parts for the rackmounted instrument Domestic Shipping Weight 45 lbs (20.
Appendix A: Specifications Table A-19: Generator Control Capabilities Description Generator Capabilities The analog and digital generators calculate signals in real time. The analog signals are derived digitally, providing a great deal of flexibility, but the output signals are restricted to those that can be realized with digital-to-analog converters and standardized sampling rates. Sine wave test signals may be swept in amplitude and frequency.
Appendix A: Specifications Table A-19: Generator Control (Cont.) Capabilities Description Time-Dependent Signals Simple user-defined audio sweeps and tone sequences are permitted. The sweep feature permits sweeping frequency and amplitude separately, or both simultaneously if necessary. The sweep test signal is a set of discrete test frequencies, not a linear sweep of frequencies from start to stop. Digital Signal Generation Digital signal generation is similar to analog signal generation.
Appendix A: Specifications Table A-20: Generator Signals Capabilities Description Generated Signals Sine A single sine-wave tone with variable amplitude and frequency. The amplitude or frequency or both may be swept or stepped to provide a wide range of sinusoidal test signals.
Appendix A: Specifications Table A-20: Generator Signals (Cont.) Capabilities Description Generated Signals Chirp A periodic sine sweep with a flat spectral distribution (equal energy per Hz of bandwidth). The chirp may optionally be restricted in bandwidth, with parameters for the lower and upper band edges. Polarity An IEC-type polarity test signal. The signal resembles a half-wave rectified sine wave with the negative values removed. Tek Polarity A Tektronix ASG100-style polarity test signal.
Appendix A: Specifications Table A-21: Audio Analyzer Application Capabilities Description Human Interface The analyzer has a touch and zoom interface. Number of Display Screens 1 Number of Measurements per Screen Up to 4 measurements at once Analysis Modes Major Modes of Operation Open Loop (External) Acquisitions are controlled by the received signal.
Appendix A: Specifications Table A-21: Audio Analyzer Application (Cont.) Capabilities Description Acquisition Modes Sweep Detection Automatic sweep detection will be present for detecting the beginning of sweeps in open-loop mode The user can indicate whether sweeps are rising or falling, and data plotting will not commence until the appropriate sweep direction is detected.
Appendix A: Specifications Table A-21: Audio Analyzer Application (Cont.) Capabilities Description Measurements X-Axis Measurements Types of measurements that may control the X-axis Frequency (received or generated) Level Filters This application gives the user a choice of several predefined filters.
Appendix A: Specifications Table A-22: FFT Analyzer Capabilities Description Frequency Related Characteristics Span (bandwidth of the displayed data) Span is dependent on the input and Zoom as shown in the following table for typical inputs and sampling rates. Input A-42 Sampling Rate Width Zoom Factor High Res 48 kHz 200.156 400.312 800.624 1000.78 2000.56 4003.12 5003.9 10007.8 20015.6 100 50 25 20 10 5 4 2 1 (full) High Bw 192 kHz 16012.5 20015.6 40031.2 80062.
Appendix A: Specifications Table A-22: FFT Analyzer (Cont.) Capabilities Description Frequency Related Characteristics Measurement Range High Resolution Mode DC to 20 kHz High Bandwidth Mode DC to 80 kHz Displayed Bins Zoomed 16 Unzoomed 428 Bin Width 0.781 Hz (minimum span) to 156.3 Hz (maximum span); calculated as span divided by 512.
Appendix A: Specifications Table A-22: FFT Analyzer (Cont.) Capabilities Description Amplitude Related Characteristics Full Span FFT Noise Floor Input terminated with 600 Ω or less, auto range and averaging ON.
Appendix A: Specifications Table A-22: FFT Analyzer (Cont.) Capabilities Description Cursor Functions Number of Cursors One or Two Cursor Modes The following cursor modes are provided: Continuously displayed amplitude and frequency at each cursor Peak locator function Multitone Multitone analyzer is a measurement that may be run in the FFT application. When the user turns on the multitone analysis mode, the AM700 starts looking for a multitone signal.
Appendix A: Specifications Table A-22: FFT Analyzer (Cont.) Capabilities Description Multitone Multitone Detection Each channel can be set to recognize one multitone, which can either be the current tone in one of the generator channels or a multitone described in a file. Files are provided in the AM700 file system that contain multitone specifications for the Tektronix ASG 100/140 audio generators.
Appendix A: Specifications Table A-23: Audio Monitor Capabilities Description Human Interface This application has the primary use of verifying the presence of audio and making simple time-domain measurements of the signal amplitude.
Appendix A: Specifications Table A-23: Audio Monitor (Cont.) Capabilities Description Oscilloscope Display Time Base Range Four samples per screen to 48000 samples per screen, continuously variable with touch-andzoom. Trigger Sources Channel 1 (A channel) Channel 2 (B channel) External (rear-panel TTL input trigger) Trigger Modes Auto New data is displayed in the absence of an edge trigger being detected. Normal New data is displayed only following detection of a trigger.
Appendix A: Specifications Table A-24: Digital Interface Tester Capabilities Description Intended Use The digital interface tester application is used to monitor and troubleshoot the digital audio interface. It allows you to view incoming data streams at the logical (bit), or electrical interface level, and to create special signals to probe the interface. Number of Primary Modes There are four major modes of operation.
Appendix A: Specifications Table A-24: Digital Interface Tester (Cont.) Capabilities Description Eye Diagram Displays a “cloud of dots” representing an equivalent-time sampled time-domain graph of the digital main inputs.
Index
Index A Accessories Non Tektronix supplied, 1-12 Optional, 1-12 Standard, 1-12 Advanced Analog Controls, 4-32 Distortion Reduction, 4-32 Output Impedance, 4-33 Advanced Digital Audio, 4-24 Channel Status Mode, 4-25 Dither Type, 4-25 Sample Rate, 4-24 Word Size, 4-25 Advanced Digital Interface, 4-29 AES REF connector, 2-40 AES/EBU Digital Generator, 4-14 AES/EBU Standard, 4-107 AM700 Audio Generator Capabilities, 1-3 file structure, 4-132 Measurement Capabilities, 1-3 AM700 Configuration, 3-1 AM700 State Sav
Index B backspace key, 2-29 Bar Graph display, FFT Analyzer, 4-85 Battery-life, reduced, 1-11 BH4 (Blackman–Harris) Window, 4-83 bin resolution, FFT Analyzer, 4-89 Bit Activity display, 4-107 Bit Probability Display, Bit Activity, 4-112 BNC Output, Digital (rear panel), 4-124 BNC Unbalanced IN/OUT, 2-40 Brightness, Display, 2-19 C Calibration, 3-18 Touch Screen, 1-8 CCIF IMD, 4-6 Channel Status, Digital Interface Tester, 4-107 Channel Status Bits, 4-25 Channel Status display, ones and zeros, 4-113 Channel
Index Controls Basic, 2-1 front panel, 2-2 Conversions Standards, 3-18 Copy destination, 3-15 format, 3-14 styles, 3-16 Copy button, 2-21 Copy Menu, 3-13 Creating a Function, 2-22, 4-129 Creating a sweep list, 4-21 crosstalk, 4-52, 4-57 Cursors Audio Monitor, 4-101 FFT Analyzer, 4-88 cursors in a frozen display, 2-10 numerical display, 2-10 Cursors button, 2-10 Cursors menu, 2-11 D dBm Input conversion factor, 3-20 Output conversion factor, 3-18 Decoded Channel Status, Digital Interface Tester, 4-114 defa
Index Digital Sample Rates, 4-24 Digital Sampling Rate, external device, 2-41 Digital sound, 2-27 Digital User Bits, 4-26 Digital Word, bit size, 4-112 Digital Word Size, 4-25 Digital XLR (rear panel), output voltage, 4-123 digitizing oscilloscope, 2-15 Display, icons, 2-4 Display button, 2-19 Display objects, 2-2 Display Type, Audio Analyzer, 4-74 Displays, graphical, 2-6 Distortion Reduction, Analog Generator, 4-32 Dither Type, 4-33, 4-123 DOS floppy disk drive, 4-132 DSP Digital Generator, 4-14 DSP port
Index file deleting, 4-134 renaming, 2-20, 4-134 file structure, AM700, 4-132 File transfers, 2-19 Filter buttons, 2-10 Flat–top Window, 4-82 Floating output, 4-33 floppy disk drive, for function loading, 4-132 Follow A, 4-9 Follow Analog, 4-9 follow mode, 4-5 Freeze button, 2-10 Frequency, control knob assignment, 4-16 Frequency knob, 2-25 Generator, 4-4 Frequency Mode, 4-30 Front Panel description, 2-8 lock and unlock, 2-30 operation, 2-8 Front-Panel buttons backlights, 2-8 General Information, 2-8 gold
Index H J Hann Window, 4-82 Headphone impedance, 2-27 headphones, 2-27 Headphones output power, 2-27 History, Plot Control, 4-58 jitter, Digital Jitter Measurement, 4-119 Jitter Ampl.
Index L LF Rejection Filter 120 Hz, 4-125 1200 Hz, 4-125 Limits button, 2-9 Line Selector Switch, 2-36 List, for multitone signals, 4-13 List Editor, for sweeps, 4-21 Long Cable Simulator, 4-31, 4-124 long cable simulator, in eye diagram display, 4-117 loss of retained data, 1-11 M Main Menu Audio Monitor, 4-103 Digital Interface Tester, 4-122 Main Output Interface Amplitude, 4-31 Mains line fuse, 1-6 Mains Power Cord, Options, 1-7 Mains power cord, 1-6 Mains Power Switch, 2-36 Manual Input Range Setting,
Index Options, 1-11 Other button, 2-16 Output Impedance.
Index Serial Ports, 2-37 Set Ref, 2-29 Generator, 4-35 Set Ref key, 2-30 Settled Level Min.
Index Sweep direction, 4-20 frequency sweep, 4-21 independent operation, 4-21 list or file, 2-28 Points, Dwell, and Time, 4-21 voltage sweep, 4-21 Sweep Control, 4-19 Sweep count, 2-28 Sweep Detection off, 4-61 on, 4-62 Sweep Detection Controls, Audio Analyzer, 4-61 Sweep List, 4-21 Sweep Modes, 4-21 Sweep/Run, 2-28 System Calibration, 3-17 System Clock Setting, 1-10 setting, 3-13 System Communications, 3-16 System Control buttons, 2-9 System Conversions Standards, 3-18 System Copy, 3-13 System Setup, soft
Index User Window file, 4-84 user-defined measurement sequence, 4-134 Utilities buttons, 2-17 V Valid measurements, Audio Analyzer, 4-52 Variable Freq.
Index Index-12 AM700 Audio Measurement Set User Manual
