Model DP524 Two-Channel AC-2 / AC-3 Digital Audio Decoder Users' Manual MAIN
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Users' Manual For Model DP524 AC-2 / AC-3 Two-Channel Digital Audio Decoder Dolby Laboratories Incorporated U.S.A. 100 Potrero Avenue, San Francisco, CA 94103 Tel: 415-558-0200; Fax: 415-863-1373 U.K. Wootton Bassett, Wiltshire SN4 8QJ Tel: 01793-842100; Fax: 01793-842101 DISCLAIMER OF WARRANTIES: Equipment manufactured by Dolby Laboratories is warranted against defects in materials and workmanship for a period of one year from the date of purchase.
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TABLE OF CONTENTS SECTION 1 Introduction 1.1 Introduction ................................................................................................... 1-1 1.3 Dolby AC-3 and AC-2................................................................................... 1-2 1.4 Data Rates, Sample Rates and Channels ....................................................... 1-3 1.5 Regulatory Notices ........................................................................................
SECTION 6 Interface Specification and Description 6.1 DP524 Interface Specifications ..................................................................... 6-1 AES/EBU Digital Audio Output, J101 ................................................... 6-1 S/PDIF Digital Audio Output, J102 ........................................................ 6-1 Encoded Data In and Timing, J103, 37-pin D-connector:....................... 6-1 Status / Control, J104, 25-pin D-connector:...........................................
SECTION 1 INTRODUCTION 1.1 Introduction The Dolby Model DP524 is a digital audio decoder unit supporting both Dolby AC2 and Dolby AC-3 digital audio coding algorithms. The unit supports up to two channels of audio. The data rates available are considerably lower than that required to convey conventional PCM data (between 40k and 384k bits/sec) yet provide exceedingly high audio quality. The unit automatically configures itself for the appropriate data rate, sample rate and algorithm type.
1-2 1.2 1.3 Features • Automatic algorithm, data rate and sample rate selection • Dolby AC-3 audio coding algorithm from 40 kbps - 384 kbps • Mono, Dual-Mono or Stereo modes for AC-3 • Dolby AC-2 audio coding algorithm from 128 kbps - 384 kbps • Mono 2-channel modes for AC-2 • Analog outputs with 20-bit D/A converters • Digital outputs (AES/EBU and S/PDIF) • Software download capability for software upgrades • Selectable auxiliary data rates (0 - 9600 baud).
1-3 1.4 Data Rates, Sample Rates and Channels Possible AC-3 Data Rates, Sample Rates and Number of Channels Data Rate 40 kbps 48 kbps 56 kbps 64 kbps 80 kbps 96 kbps 112 kbps 128 kbps 160 kbps 192 kbps 224 kbps 256 kbps 320 kbps 384 kbps Sample rate 32kHz, 44.1kHz or 48kHz 32kHz, 44.1kHz or 48kHz 32kHz, 44.1kHz or 48kHz 32kHz, 44.1kHz or 48kHz 32kHz, 44.1kHz or 48kHz 32kHz, 44.1kHz or 48kHz 32kHz, 44.1kHz or 48kHz 32kHz, 44.1kHz or 48kHz 32kHz, 44.1kHz or 48kHz 32kHz, 44.1kHz or 48kHz 32kHz, 44.
1-4 1.5 Regulatory Notices FCC This equipment has been tested and found to comply with the limits for a Class A digital device, pursuant to part 15 of the FCC Rules. These limits are designed to provide reasonable protection against harmful interference when the equipment is operated in a commercial environment.
1-5 IEC NOTICES IMPORTANT SAFETY NOTICE This unit complies with the safety standard IEC65. To ensure safe operation and to guard against potential shock hazard or risk of fire, the following must be observed: o Ensure the voltage selector is set to the correct mains voltage for your supply. o Ensure fuses fitted are the correct rating and type as marked on the unit. o The unit must be earthed by connecting to a correctly wired and earthed power outlet.
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SECTION 2 APPLICATIONS The Dolby Model DP524 is suitable for a variety of point-to-point and point-tomultipoint digital transmission applications, including cable, telecommunications and satellite or terrestrial microwave links. The very high audio quality and low, spectrum-efficient data rates of the AC-2 and AC-3 coding process make them particularly appropriate for these applications. 2.
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SECTION 3 PRE-INSTALLATION 3.1 Unpacking Before proceeding further, be sure to inspect the outer carton for shipping damage. If there has been any penetration to the carton, be sure to inspect the unit for any physical damage in those areas. Several accessories have been provided in the packet provided with this manual. Please compare them with the following list to ensure that there are no missing items: Rack screws and washers Power cord Spare fuse 1A (Part. No.
3-2 OPEN THE DOOR FUSE ACTIVE FUSE CARRIER (LOWER) Check that the fuse in the active (lower) fuse carrier is of the correct rating. A spare fuse can be stored in the upper fuse carrier position. Snap the fuse compartment door closed. Internal Fuse The switching power supply contains a separate fuse. Most fault conditions should be protected by the main fuse. The internal fuse rating is: 2 Amp, 250V, 20 mm, fast-blow. 3.
3-3 front, rear, and each of the sides of the unit. The three black screws should be reserved for affixing at the front. Note The front panel is attached to the top cover by means of 4 screws also affixing the handles. These do not need to be removed. By grasping the front panel handles, gently pull the top cover/front panel assembly forward then away towards the rear. Carefully set aside this subassembly. Reverse the above procedure when re-assembling the unit.
3-4 3.4.1 Jumpers for Encoded Data In & Timing (J103) Receive Timing J205 / Receive Data J206 [terminated] Termination resistors (150 ohms) are provided across the "RT" and "RD" inputs. These inputs are terminated in the default configuration, which should be appropriate for most applications. Certain situations may require that these inputs be unterminated (e.g., multiple inputs driven from a single output).
3-5 Note Switch positions 5 and 6 take on two roles: • They set the Aux Data output baud rate when S101-2 is in the Normal position and S101-4 is in the • • Aux Data position They set the Download baud rate when S101-2 is in the Download position. Their positions are immaterial when S101-2 is in the Normal position and S101-4 is in the Command position; the Command baud rate is at a fixed 9600 baud. 3.5.1 Switch nos.
3-6 3.5.3 Switch no. 3 - Digital Output Format Selection [up] Position this switch to corresponds to the type of digital output signal format. Refer to Section 4 for information regarding audio connections. Format S/PDIF AES/EBU S101-3 Down [Up] The switch setting selects how the digital bit stream is marked. S/PDIF is synonymous with "consumer" format, AES/EBU is synonymous with "professional" format.
SECTION 4 INSTALLATION 4.1 Mounting The DP524 is designed for 19 inch rack mounting, but may be mounted in any plane and with any orientation. It occupies 1U (1 3/4") of space. When mounting the unit, ensure that there is air flow around it, and that it is not mounted directly above any equipment generating high amounts of heat. The unit will operate within specifications up to a maximum ambient temperature of 50° C (122° F).
4-2 For optimum immunity to radio-frequency interference, cable shields must be connected to the shells of the XLR connectors, not to pin 1. In an installation where the source is unbalanced, avoid ground loops by using two conductor shielded cable exactly as for balanced circuits; in other words, ensure that the unbalancing (connecting the wire to pin 3 to ground) occurs only at the end remote from the Model DP524.
4-3 Baud Rate 0 1200 2400 9600 S101-5 Down Down Up Up S101-6 Down Up Down Up Where is baud rate of the Encoder (generating the Aux data stream) is higher than the baud rate of the Decoder it is possible that data may be lost. 4.3.3 RS-422 (J106) The RS-422 connection is not supported in this product. 4.3.4 Parallel Status and Control (J104) It is possible to remotely enable the Test Tone and Download functions: By taking pin 19 of the J104 to +5V, the Test Tone is enabled.
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SECTION 5 OPERATION Once the DP524 is installed and operational, no user-intervention is required. In normal operation, one of the Green LEDs will indicate the incoming sample rate (32kHz , 44.1 kHz or 48 kHz); the signal presence indicators will also illuminate if appropriate. 5.1 Front Panel Status Indicators Fault The Fault LED indicates power supply or processor/memory failure.
5-2 5.2 Rear Panel Level Controls Each analog output connector has a level control adjacent to it. Each analog output is adjustable (at full scale) over a range of below 0dBu to greater than +24dBu. 5.3 Test Tone Level The operating level for the test tone generator of the Model DP524 is -18dB relative to full scale. This is useful when calibrating the analog outputs and also for checking proper operation of the digital outputs.
SECTION 6 INTERFACE SPECIFICATION AND DESCRIPTION 6.1 DP524 Interface Specifications AES/EBU Digital Audio Output, J101 XLR-type connector, 5V p-p typical, 110 Ohms. Pin Connection 1 Digital signal ground 2 Digital Audio + 3 Digital Audio - S/PDIF Digital Audio Output, J102 BNC-type connector, 0.5V p-p typical, 75 ohms.
6-2 Status / Control, J104, 25-pin D-connector: Pin 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 Connection NC NC NC NC NC NC NC NC NC Comments Do Not Connect Do Not Connect Do Not Connect Do Not Connect Do Not Connect Do Not Connect Do Not Connect Do Not Connect Do Not Connect Do Not Connect Do Not Connect Do Not Connect Logic Level Reference (+5V) Digital ground Digital ground Digital ground Digital ground Digital ground Input, Enable Test Tone Input, Enable Software Download Outpu
6-3 6.2 RS-449 Interface Description 6.2.1 Functional Description The Dolby Model DP524 provide a standard RS-449 interface in the type DT mode (data and timing signals only, no handshakes) through 37-pin male D-connectors. RS-449 is the mechanical specification for a balanced (differential) transmission system meeting RS-422 and RS-423 electrical specifications.
6-4 6.2.3 Back-to-Back Testing For purposes of testing the Model DP523 and Model DP524 in a back-to-back configuration, a special cable must be constructed. Note that a DTE-to-DTE connection is not supported by the RS-449 specification. A standard 37-wire cable cannot be used to interconnect the units. The special cable connects the TT outputs of the DP523 directly to the ST inputsof the DP523 and to the RT inputs of the DP524.
6-5 6.3 Serial Control It is possible to command the DP524 via the RS-232 port, J105 on the rear of the unit when the Command/Aux data switch (S101-4) is in the Up position. The communications protocol for command mode is fixed at 9600 baud, 1 stop bit, no parity. Note This port cannot be used simultaneously for external control and Auxiliary Data output.
6-6 Command $18: Return System Status $FB $20 $18 0 $FD The unit returns the following byte: B7 0 B6 Dr_lock B5 Sr_lock B4 Test B3 48kHz B2 44.1kHz B1 32kHz B0 Mute Each bit is returned set if the associated signal is active. Dr_lock and Sr_lock are internal signals. Dr_lock is active when the decoder has successfully locked to the incoming RS-449 clock 'RT' : Receive Timing.
6-7 This command will return $FF if the decoder is in Test Tone mode or if the decoder is in normal mode but does not have an input data clock that it can lock to.
6-8 Command $42: Set Compression mode $FB $20 $42 data $FD Where data is as follows: B7 0 B6 0 B5 0 B4 0 B3 0 B2 0 B1 C1 C0 and C1 are defined as follows: C1 C0 Comment 0 0 Custom mode, no digital dialog normalization 0 1 Custom mode, digital dialog normalization 1 0 Line Out Mode 1 1 RF mode MAIN B0 C0
SECTION 7 DP524 SPECIFICATION Specifications1 Italics = nomenclature for panel markings, switch labels, jumpers, LEDs, etc. All inputs and outputs are TTL compatible unless otherwise stated. Frequency Response Lower limit: 20 Hz. Upper limit varies from 8 to 20 kHz depending on algorithm. Tolerance ± 0.3 dB. Distortion2 AC-2 Less than 0.1 % at 1 kHz. Less than 0.2 %, 20 Hz - algorithm upper limit. AC-3 Less than 0.005 %, 20 Hz - algorithm upper limit.
7-2 Digital Audio Outputs AES/EBU, 3-pin XLR-type, male, balanced , 110 ohms ±5%, 5Vpp nominal. S/PDIF, BNC female connector, unbalanced, 75 ohms ±5%, 0.5Vpp nominal. Data Output / Command Input RS232, Male 9-pin D connector. RS-422, Female 25-pin D connector. These connectors may be used to load software upgrades into the unit, allow serial control of the unit or to output auxiliary data. Mode and Baud Rate of the serial ports are set by the rear panel switch.
7-3 General Power Requirements 90-260 VAC, 50-60 Hz, 24VA Dimensions and Weight 1- ¾ x 19 x 11- ¾ inches (4.45 x 48.26 x 29.8 cm), 8.5 pounds (3.9 kg), approx. Emissions Complies with the limits for a Class A digital device, pursuant to Part 15 of the FCC Rules. Environmental Requirements Temperature Operating : 0 oC to 50 oC, natural convection cooling. Non-operating (Storage): -40 oC to 85 oC. Warranty 1-year limited, parts and labor.
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