User Manual CFG280 11 MHz Function Generator 070-8559-03
Copyright Tektronix, Inc. 1991. All rights reserved. Tektronix products are covered by U.S. and foreign patents, issued and pending. Information in this publication supercedes that in all previously published material. Specifications and price change privileges reserved. Tektronix, Inc., P.O. Box 1000, Wilsonville, OR 97070–1000 TEKTRONIX and TEK are registered trademarks of Tektronix, 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.
Table of Contents General Safety Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . iii Getting Started . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Preparing the Function Generator for Use . . . . . . . . . . . . . . . . . Front Panel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Rear Panel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 2 4 8 Reference . . . . . . . . . . . . . . . . . . .
Table of Contents ii CFG280 User Manual
General Safety Summary Review the following safety precautions to avoid injury and prevent damage to this product or any products connected to it. Injury Precautions Use Proper Power Cord To avoid fire hazard, use only the power cord specified for this product. Avoid Electric Overload To avoid electric shock or fire hazard, do not apply a voltage to a terminal that is outside the range specified for that terminal.
General Safety Summary Do Not Operate in Wet/Damp Conditions To avoid electric shock, do not operate this product in wet or damp conditions. Do Not Operate in Explosive Atmosphere To avoid injury or fire hazard, do not operate this product in an explosive atmosphere. Product Damage Precautions Use Proper Voltage Setting Before applying power, ensure that the line selector is in the proper position for the power source being used.
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 vi CFG280 User Manual
Getting Started The Tektronix CFG280 Function Generator produces low distortion sine waves, square waves, triangle waves, TTL sync signals, positive and negative pulses, and ramp waveforms in a frequency range of 0.1 Hz to 11 MHz. You can also directly control amplitude and DC offset. The sweep function makes the output signal traverse a range of frequencies.
Getting Started Preparing the Function Generator for Use Check the following items prior to operating the CFG280 Function Generator for the first time (see Figure 1 for locations of items 1 through 3): 2 1 3 Figure 1: Line Voltage Selectors, Power Input, and Fuse Locations CAUTION. To prevent damage to the instrument, set the line voltage selectors to the proper voltage setting and install the correct line voltage fuse before operating the equipment. 1.
Getting Started WARNING. To prevent electrical shock, unplug the power cord and disconnect the signal cable from any signal source before checking or replacing the fuse. 2. Check that the correct line fuse is installed. The line fuse provides protection if the equipment malfunctions or an overload occurs. Refer to Appendix C: Replaceable Parts on page 29 for fuse part numbers. WARNING. To prevent electrical shock, connect the power cord to a properly grounded power source.
Getting Started Front Panel Figure 2 shows the front-panel controls, connectors, and indicators of the CFG280 Function Generator. 1 2 3 4 5 6 7 8 12 13 14 15 25 24 23 22 21 9 16 20 10 11 17 19 18 Figure 2: Front Panel Controls, Connectors, and Indicators 1. OVERRANGE LED. Lights if you apply a frequency above specified limits to the EXT COUNTER INPUT connector. It also lights if the gate time is too slow for the incoming signal. 2. GATE LED.
Getting Started The 1 and 0.1 LEDs provide accurate indication for the two lowest frequency ranges. For example, if the FREQUENCY dial is set on 2.6 and the 1 LED is lighted, the function generator output frequency is 2.6 Hz. 5. FREQUENCY Range LEDs. Indicate the range (either MHz or kHz) of the reading shown on the counter readout. These LEDs also indicate the frequency range of the function generator output.
Getting Started Table 1: Effect of Symmetry Buttons on Output Waveform Left Symmetry Button Right Symmetry Button 10. SWEEP Button. Activates the internal sweep generator, which produces a signal that traverses a range of frequencies. This button enables the SWEEP RATE and SWEEP WIDTH knobs. You can also feed an external sweep signal into the CFG280 Function Generator through a connector on the rear panel. See External Sweep on page 11 for further details. 11. SWEEP RATE Knob.
Getting Started 14. SOURCE Button. Selects between internal and external counter input. When you push the button in, the counter readout displays the signal frequency count from the EXT COUNTER INPUT. When you push the button out the counter readout displays the frequency count of the signal being generated by the CFG280 Function Generator. 15. MAIN Button. Selects between two voltage ranges: 0 Vp-p to 2 Vp-p or 0 Vp-p to 20 Vp-p.
Getting Started Rear Panel In addition to the line voltage switches, fuse, and power cord receptacle, the items shown in Figure 3 are located on the rear panel. 1 2 3 Figure 3: Rear Panel Connections CAUTION. To avoid the risk of fire or damage to theCFG280 Function Generator, be sure input equipment is properly grounded before connecting it to the function generator. 1. GATE INPUT BNC. This connector accepts external gate signals, which you can use in tone-burst generation. See page 13 for details. 2.
Reference This section describes several advanced functions of the CFG280 Function Generator. The variety of swept and modulated signals available from the function generator make it especially useful for such applications as testing servo-system or amplifier response, distortion, and stability. It can be used for FM generation, frequency multiplication, or as a variable, beat-frequency oscillator. It can be used to generate repetition rates or tone bursts.
Reference 3. Change the FREQUENCY range and rotate the FREQUENCY dial. Observe how the frequency of the TTL signal changes. 4. Rotate the DC OFFSET knob. Notice that this knob has no effect on TTL signals. The DC OFFSET knob has no effect because the DC offset of a TTL signal is standardized for compliance with TTL logic. Signals produced from the SYNC OUT connector are not affected by this knob. 5. Rotate the AMPLITUDE knob. Notice that this knob has no effect on TTL signals.
Reference 3. Connect another channel of the oscilloscope to the device under test (see Figure 5). 4. Push the SWEEP button out on the function generator to deactivate the internal sweep function. 5. Turn the FREQUENCY dial to the desired sweep start frequency (the lowest point on the sweep). 6. Push the SWEEP button in to enable the internal sweep function. 7. Pull the SWEEP RATE knob out to lock the function generator at the sweep stop frequency (the highest point on the sweep). 8.
Reference 2. Turn the Frequency Dial to the 0.1 position. CAUTION. To avoid damage to the CFG280, ensure that the maximum voltage into the rear panel VCF INPUT is no more than ±10 V pk. 3. Connect an external voltage signal to the VCF INPUT on the rear panel of the instrument (see Figure 6). 4. Push the SWEEP button out to deactivate the internal sweep function. When using an external sweep signal, the SWEEP WIDTH and SWEEP RATE knobs have no effect on the signal sweep.
Reference 2. Push the sine wave FUNCTION button. 3. Set the FREQUENCY dial to the desired carrier frequency. CAUTION. To avoid damage to theCFG280 Function Generator, ensure that the maximum voltage into the rear panel VCF INPUT is no more than 5 Vp-p . 4. Connect an external voltage signal to the EXT AM INPUT on the rear panel of the instrument (see Figure 7). 5. Control the amplitude modulation by varying the voltage level of the external voltage source.
Reference CFG253 To VCF INPUT (on rear panel) Ramp Generator To GATE INPUT (on rear panel) Test oscilloscope CFG280 MAIN OUT EXT IN RAMP OUT Figure 8: Tone-Burst and Stepped Frequency Multiplication Test Setup 3. Connect the MAIN OUTPUT of the CFG253 to a BNC T connector. Connect the BNC T outputs to the GATE INPUT connector on the CFG280 Function Generator and the external input on the ramp generator (see Figure 8). 4. Set the ramp generator to generate the desired ramp duration and polarity. 5.
Reference VCF input GATE input Tone-Burst or stepped frequency output Figure 9: Tone-Burst and Stepped Frequency Typical Waveforms 7. Select the sweep frequency range by adjusting the FREQUENCY dial to one end of the swept range (upper or lower limit, depending on the polarity of the ramp) and adjusting the other end with the RG501 output amplitude.
Reference 16 CFG280 User Manual
Appendix A: Specifications Tables 2 through 5 show characteristics of the CFG280 Function Generator that are guaranteed by warranty. Table 2: Generator Specifications Characteristic Measurement Outputs Square wave, sine wave, triangle wave, TTL pulse, positive and negative ramp, pulse and skewed sine wave, AM, and sweep functions Frequency Ranges 0.1 Hz to 11 MHz, up/down range switchable in eight decade steps Dial Range 1 to 11 calibrated 0.
Appendix A: Specifications Table 2: Generator Specifications (Cont.) Characteristic Measurement Amplitude Flatness (At 10 kHz, 50 Load) Within ±0.5 dB, 0.1 Hz to 110 kHz Within ±1.5 dB, to 1.1 MHz Within ±2.5 dB, to 11 MHz Sine Wave Distortion <1% from 10 Hz to 100 kHz –30 dB at all other frequencies (ambient temperature 20_ C to 30_ C) Triangle Wave Linearity 0.
Appendix A: Specifications Table 3: Counter Specifications Characteristic Measurement Input Selection Internal and external input selectable Frequency Range DC to 100 MHz for internal 1 Hz to 100 MHz, AC coupled for external Resolution Frequency mode: 1 Hz, 10 Hz, 1 kHz Period mode: 1 ms Accuracy Frequency mode: ±(1 count + time base error) Period mode: ±(1 count + time base error + trigger error) External Input Sensitivity 1 Hz to 50 MHz 50 MHz to 100 MHz Impedance 1 M pa
Appendix A: Specifications Table 4: General Specifications Characteristic Measurement Line Voltage Range Selectable ranges at 50 Hz to 60 Hz 90 VAC to 110 VAC 108 VAC to 132 VAC 198 VAC to 242 VAC 216 VAC to 250 VAC Operating Temperature +0_ C to +40_ C, 80% relative humidity Nonoperating Temperature –10_ C to +70_ C, 70% relative humidity Table 5: Certifications and Compliances EC Declaration of Conformity – EMC Meets intent of Directive 89/336/EEC for Electromagnetic Compatibility.
Appendix A: Specifications Table 6: Typical Mechanical Specifications Characteristic Measurement Dimensions (H x W x D) 100 mm X 240 mm X 230 mm (3.9 in x 9.5 in x 9.0 in) Weight 3.0 kg (6.
Appendix A: Specifications 22 CFG280 User Manual
Appendix B: Maintenance This appendix provides information for the basic maintenance of the CFG280 Function Generator. Cleaning To clean the CFG280 Function Generator, use a soft cloth dampened in a solution of mild detergent and water. Do not spray cleaner directly onto the instrument, since it may leak into the cabinet and cause damage. Do not use chemicals containing benzine, benzene, toluene, xylene, acetone, or similar solvents. Do not use abrasive cleaners on any portion of the function generator.
Appendix B: Maintenance Troubleshooting Use the following diagrams to identify basic problems with your instrument setup. The diagrams do not provide instructions for or recommend instrument disassembly. If these diagrams fail to solve your problem, send your instrument to the nearest Tektronix service center. NOTE. These diagrams assume that any other test equipment you use is operating properly. Before you assume a problem exists with theCFG280 Function Generator, check all other test equipment.
Appendix B: Maintenance Inappropriate Counter Reading Start. Is the digital display frozen? No Are function, gate, and attenuation settings appropriate for the input signal? No Change settings to accommodate the input signal. Yes Yes Send your instrument to the nearest Tektronix service center. Are you using the external input connector? No Toggle the SOURCE button. Yes Check connection and voltage level of signal.
Appendix B: Maintenance No Function Generator Output Start. Is the digital display blank? Yes Go to Digital Display Blank on page 24. No Does oscilloscope have good connection to output jack? No Ensure good electrical connection to output jack. Yes Are amplitude settings too low to produce visible signal? Yes Adjust with AMPLITUDE knob and MAIN button. No Are range and function selected? No Push appropriate MULTIPLIER and FUNCTION buttons.
Appendix B: Maintenance Inappropriate Function Generator Output Start. Is signal amplitude too large or too small? Yes Adjust with AMPLITUDE knob and MAIN button. No Is signal frequency too fast or slow? Yes Adjust with MULTIPLIER buttons and FREQUENCY dial. Push in SWEEP button to activate internal sweep. No No Is signal responsive to sweep rate and sweep width adjustments? No Are you using internal or external sweep? External Sweep knobs do not function in external sweep mode.
Appendix B: Maintenance 28 CFG280 User Manual
Appendix C: Replaceable Parts Replaceable parts may be ordered directly from your authorized Tektronix dealer. Standard Accessories The following items are shipped with the CFG280 Function Generator: Table 7: Standard Accessories Accessory Tektronix Part Number Fuse, 3AG, 0.
Appendix C: Replaceable Parts The following power cords are available.
