Model DP524
MAIN
Two-Channel AC-2 / AC-3
Digital Audio Decoder
Users' Manual
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Users' Manual
MAIN
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
Equipment manufactured by Dolby Laboratories is warranted against defects in materials and
DISCLAIMER OF WARRANTIES:
workmanship for a period of one year from the date of purchase. All warranties, conditions or other terms implied by statute are excluded to
the fullest extent allowed by law.
LIMITATION OF LIABILITY:
negligence or otherwise shall not exceed the cost of repair or replacement of the defective components and under no circumstances shall
Dolby Laboratories be liable for incidental, special, direct, indirect or consequential damages (including but not limited to damage to software
or recorded audio or visual material), or loss of use, revenue or profit even if Dolby Laboratories or its agents have been advised, orally or in
writing, of the possibility of such damages.
This unit complies with the EMC requirements of prEN55103-1 and -2 when installed in accordance with this manual in an E2 environment
It is understood and agreed that Dolby Laboratories’ liability whether in contract, in tort, under any warranty, in
Dolby and the double-D symbol are registered trademarks of Dolby Laboratories Licensing Corporation.
©1998 Dolby Laboratories Inc.
ISSUE 3
S98/10536/11869
Dolby Part No. 91394
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SECTION 1 Introduction
MAIN
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........................................................................................1-4
SECTION 2 Applications
SECTION 3 Pre-Installation
3.1 Unpacking......................................................................................................3-1
3.2 Inspection ......................................................................................................3-1
3.2.1 Claims for Shipping Damage ......................................................3-1
3.3 Fusing Information........................................................................................3-1
Main Fuse................................................................................................3-1
Internal Fuse............................................................................................3-2
3.4 Configuring Jumper Settings.........................................................................3-2
3.4.1 Jumpers for Encoded Data In & Timing (J103)............................3-4
Receive Timing / Receive Data Termination..............................3-4
Request to Send / Terminal Ready Enable..................................3-4
3.4.2 Signal Ground-to-Chassis Link...................................................3-4
3.5 Configuring the Rear Panel DIP Switch S101...............................................3-4
3.5.1 Switch nos. 1, 7 & 8 - Test Tone.................................................3-5
3.5.2 Switch nos. 2, 5 & 6 Software Download..................................3-5
3.5.3 Switch no. 3 - Digital Output Format Selection..........................3-6
3.5.4 Switch nos. 4, 5 & 6 - Command/Aux Data................................3-6
TABLE OF CONTENTS
SECTION 4 Installation
4.1 Mounting.......................................................................................................4-1
4.2 Audio Connections........................................................................................4-1
4.2.1 S/PDIF Output - J102..................................................................4-1
4.2.2 AES/EBU Output - J101 .............................................................4-1
4.2.3 Analog Outputs - J106/7..............................................................4-1
4.3 Data, Status, and Remote Control Connections ............................................4-2
4.3.1 Encoded Data In & Timing - J103...............................................4-2
4.3.2 RS-232 (J105)..............................................................................4-2
4.3.3 RS-422 (J106)..............................................................................4-3
4.3.4 Parallel Status and Control (J104)...............................................4-3
SECTION 5 Operation
5.1 Front Panel Status Indicators.........................................................................5-1
5.2 Rear Panel Level Controls.............................................................................5-2
5.3 Test Tone Level.............................................................................................5-2
5.4 Software Downloading Procedure.................................................................5-2
SECTION 6 Interface Specification and Description
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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:............................................ 6-2
RS-232 Port, J105 ................................................................................... 6-2
Analog Audio Input, J106 & J107 .......................................................... 6-2
6.2 RS-449 Interface Description........................................................................ 6-3
6.2.1 Functional Description................................................................... 6-3
6.2.2 Interface Timing............................................................................. 6-3
6.2.3 Back-to-Back Testing..................................................................... 6-4
6.3 Serial Control ................................................................................................6-5
6.3.1 System related commands........................................................... 6-5
6.3.2 AC-3 Related commands ............................................................ 6-7
SECTION 7 Product Specifications
1.1 Introduction
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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.
Both digital (AES/EBU and S/PDIF) and analog outputs are provided.
A full duplex serial control system has also been implemented which allows the user
to retrieve Status or Aux. data from the decoder. It is also possible for the user to
update the units software revision by means of a serial download capability.
SECTION 1
INTRODUCTION
The decoder provides front panel system status indicators as well as the ability to
respond to serial inquiries relating to system status.
A digitally generated test signal is provided for system alignment and
troubleshooting and can be activated from a rear panel switch or via the serial
control system.
Rear panel analog output level trimmers are provided.
This manual includes installation procedures, descriptions of Model DP524
operation, and interface specifications.
1.2 Features
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• 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).
• RS-232 and RS-422 serial interfaces allows Control, Status, Software
Download and Auxiliary data.
• Built-in test tone generator
1.3 Dolby AC-3 and AC-2
1-2
Despite the low, spectrum-efficient data rate, Dolby AC-3 and AC-2 yield very high
audio quality and is suitable for the most demanding of professional and consumer
distribution applications. First demonstrated to the film industry in May of 1991,
Dolby AC-3 audio coding technology has evolved into a very sophisticated and
flexible system for the digital representation of high quality sound. Dual channel
implementations of the AC-3 algorithm can be user-configured to operate in Dual
Mono or Stereo modes.
AC-3 and AC-2 are compatible with Dolby Matrix Surround decoding. A wide
range of bit rates and audio coding modes are supported with this audio coding
technique, and are summarized in the tables on the following page.
1-3
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1.4 Data Rates, Sample Rates and Channels
Possible AC-3 Data Rates, Sample Rates and Number of Channels
Data Rate Sample rate Channels
40 kbps 32kHz, 44.1kHz or 48kHz Set by Encoder
48 kbps 32kHz, 44.1kHz or 48kHz Set by Encoder
56 kbps 32kHz, 44.1kHz or 48kHz Set by Encoder
64 kbps 32kHz, 44.1kHz or 48kHz Set by Encoder
80 kbps 32kHz, 44.1kHz or 48kHz Set by Encoder
96 kbps 32kHz, 44.1kHz or 48kHz Set by Encoder
112 kbps 32kHz, 44.1kHz or 48kHz Set by Encoder
128 kbps 32kHz, 44.1kHz or 48kHz Set by Encoder
160 kbps 32kHz, 44.1kHz or 48kHz Set by Encoder
192 kbps 32kHz, 44.1kHz or 48kHz Set by Encoder
224 kbps 32kHz, 44.1kHz or 48kHz Set by Encoder
256 kbps 32kHz, 44.1kHz or 48kHz Set by Encoder
320 kbps 32kHz, 44.1kHz or 48kHz Set by Encoder
384 kbps 32kHz, 44.1kHz or 48kHz Set by Encoder
Possible AC-2 Data Rates, Sample Rates and Number of Channels
Data Rate Sample rate Channels
128 kbps 48kHz 1
192 kbps 48kHz 1
256 kbps 48kHz 2
384 kbps 48kHz 2
1.5 Regulatory Notices
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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. This equipment generates, uses, and can
radiate radio frequency energy and, if not installed and used in accordance with this
instruction manual, may cause harmful interference to radio communications.
Operation of this equipment in a residential area is likely to cause harmful
interference in which case the user will be required to correct the interference at his
or her own expense.
1-4
UL
Troubleshooting must be performed by trained technicians. Do not attempt to
service this equipment unless you are qualified to do so.
WARNING: Check that the correct fuses have been installed. To reduce the risk of
fire, replace the fuses only with the same type and rating.
Exposed portions of the power supply are electrically "hot". In order to reduce the
risk of electrical shock, the power cord MUST be disconnected when the cover of
this equipment is removed.
UK
Connections for the United Kingdom:
WARNING: THIS APPARATUS MUST BE EARTHED
As the colours of the cores in the mains lead may not correspond with the coloured
markings identifying the terminals in your plug, proceed as follows:
• The core which is coloured green and yellow must be connected to the
terminal in the plug which is marked with the letter E or by the eart h symbol
or coloured green or green and yellow.
• The core which is coloured blue must be connected to the term inal which is
marked with the letter N or coloured black.
• The core which is coloured brown must be connected to the ter minal which is
marked with the letter L or coloured red.
1-5
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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.
o The power cord supplied with this unit must be wired as follows:
Live—Brown Neutral—Blue Earth—Green/Yellow
IMPORTANT – NOTE DE SECURITE
Ce materiel est conforme à la norme IEC65. Pour vous assurer d'un fonctionnement sans danger et de prévenir
tout choc électrique ou tout risque d'incendie, veillez à observer les recommandations suivantes.
o Le selecteur de tension doit être placé sur la valeur correspondante à votre alimentation réseau.
o Les fusibles doivent correspondre à la valeur indiquée sur le materiel.
o Le materiel doit être correctement relié à la terre.
o Le cordon secteur livré avec le materiel doit être cablé de la manière suivante:
Phase—Brun Neutre—Bleu Terre—Vert/Jaune
WICHTIGER SICHERHEITSHINWEIS
Dieses Gerät entspricht der Sicherheitsnorm IEC65. Für das sichere Funktionieren des Gerätes und zur
Unfallverhütung (elektrischer Schlag, Feuer) sind die folgenden Regeln unbedingt einzuhalten:
o Der Spannungswähler muß auf Ihre Netzspannung eingestellt sein.
o Die Sicherungen müssen in Type und Stromwert mit den Angaben auf dem Gerät übereinstimmen.
o Die Erdung des Gerätes muß über eine geerdete Steckdose gewährleistet sein.
o Das mitgelieferte Netzkabel muß wie folgt verdrahtet werden:
Phase—braun Nulleiter—blau Erde—grün/gelb
NORME DI SICUREZZA – IMPORTANTE
Questa apparecchiatura è stata costruita in accordo alle norme di sicurezza IEC 65. Per una perfetta
sicurezza ed al fine di evitare eventuali rischi di scossa êlettrica o d'incendio vanno osservate le
seguenti misure di sicurezza:
o Assicurarsi che il selettore di cambio tensione sia posizionato sul valore corretto.
o Assicurarsi che la portata ed il tipo di fusibili siano quelli prescritti dalla casa costruttrice.
o L'apparecchiatura deve avere un collegamento di messa a terra ben eseguito; anche la connessione rete deve
avere un collegamento a terra.
o Il cavo di alimentazione a corredo dell'apparecchiatura deve essere collegato come segue:
Filo tensione—Marrone Neutro—Blu Massa—Verde/Giallo
AVISO IMPORTANTE DE SEGURIDAD
Esta unidad cumple con la norma de seguridad IEC65. Para asegurarse un funcionamiento
seguro y prevenir cualquier posible peligro de descarga o riesgo de incendio, se han de observar
las siguientes precauciones:
o Asegúrese que el selector de tensión esté ajustado a la tensión correcta para su alimentación.
o Asegúrese que los fusibles colocados son del tipo y valor correctos, tal como se marca en la unidad.
o La unidad debe ser puesta a tierra, conectándola a un conector de red correctamente cableado y puesto a tierra.
o El cable de red suministrado con esta unidad, debe ser cableado como sigue:
Vivo—Marrón Neutro—Azul Tierra—Verde/Amarillo
VIKTIGA SÄKERHETSÅTGÄRDER!
Denna enhet uppfyller säkerhetsstandard IEC65. För att garantera säkerheten och gardera mot
eventuell elchock eller brandrisk, måste följande observeras:
o Konrollera att säkringarna är av rätt typ och för rätt strömstyrka så som anvisningarna på enheten föreskriver.
o Enheten måste vara jordad genom anslutning till ett korrekt kopplat och jordat el-uttag.
o El-sladden som medföljer denna enhet måste kopplas enligt foljande:
Fas—Brun Neutral—Blå Jord—Grön/Gul
BELANGRIJK VEILIGHEIDS-VOORSCHRIFT:
Deze unit voldoet aan de IEC65 veiligheids-standaards. Voor een veilig gebruik en om het gevaar van electrische
schokken en het risico van brand te vermijden, dienen de volgende regels in acht te worden genomen:
o Controleer of de spanningscaroussel op het juiste Voltage staat.
o Gebruik alleen zekeringen van de aangegeven typen en waarden.
o Aansluiting van de unit alleen aan een geaarde wandcontactdoos.
o De netkabel die met de unit wordt geleverd, moet als volgt worden aangesloten:
Fase—Bruin Nul—Blauw Aarde—Groen/Geel
GB
F
D
I
E
So Kontrollera att spänningsväljaren är inställd på korrekt nätspänning.
NL
MAIN
The Dolby Model DP524 is suitable for a variety of point-to-point and point-to-
MAIN
multipoint 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.
2.1 Cable
Whether for audio-only services or for an enhanced digital audio service
accompanying video, the DP524 is ideally suited to cable applications. The
availability of low data rates permits efficient use of cable bandwidth as either a
baseband signal or as a subcarrier above video.
SECTION 2
APPLICATIONS
2.2 Telecommunications
The Model DP524 can be used with T1 or ISDN lines for point-to-point
communications. Film and recording studios, as well as mastering facilities, can be
interconnected with audio and control data to enable multi-site, real-time
operations. Broadcast applications include STL, ICR, and backhaul operations.
Because only a small portion of the T1 bit stream is used, the residual capacity
remains available for additional audio channels or other services (e.g., voice or
computer data), or fractional service can be ordered. In ISDN applications, the
number of "B" channels needed is determined by the chosen bit rate.
MAIN
3.1 Unpacking
MAIN
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. 56016)
Spare fuse, 2A, used on the internal power supply (Part No. 56017)
Warranty card (Part No. 91292)
Communications Products Group Registration card (Part No. 91228)
SECTION 3
PRE-INSTALLATION
3.2 Inspection
Carefully remove the unit from its carton. Remove the plastic wrapping and place
on a flat surface.
If there are no signs of physical damage, proceed to "Fusing Information" below.
3.2.1 Claims for Shipping Damage
If, in your inspection procedure, you should find physical damage, please notify the
carrier immediately. All claims for damage must be filed by the recipient. Dolby
Laboratories or your dealer/distributor will be happy to assist where possible.
3.3 Fusing Information
WARNING To reduce the risk of fire, replace fuses only with the same type and rating.
The DP524 utilizes a universal switching power supply that can accommodate the
full range of nominal voltages between 90 Vac and 264 Vac and any frequency
between 50 Hz and 60 Hz.
Main Fuse
Use 1 Amp, 250V, 20 mm, Time-Lag fuse.
With a small flat-blade screwdriver, open the fuse compartment door in the AC
power input housing (see figure).
OPEN THE
MAIN
DOOR
ACTIVE
FUSE CARRIER
(LOWER)
3-2
FUSE
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.
3.4 Configuring Jumper Settings
The Model DP524 includes certain user-selectable options that are configured by
means of internal jumpers, as shown below. Their default settings (shipped with the
unit) are shown in the figure. Any jumpers not specifically mentioned are for factory
use only and should not be disturbed.
If you need to gain access to the interior of the DP524 to change these jumpers,
proceed as follows:
WARNING Be sure that the unit is NOT powered up. The power cord must not be connected.
Using a #2 Phillips head screwdriver, remove the 12 screws securing the top
cover/front panel subassembly to the chassis; there are three screws on the
3-3
MAIN
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.
1
S101
Note: Jumpers J200, 201, 202, 203,204
are not applicable to this product and should
not be disturbed. Leave them in the positions
shown.
J105
J200
J202
J201
Signal Ground to
Chassis Ground Link
[Open]
Linked
[Terminated (150 ohm)]
J3
J203
Not Terminated
J204
J205
RT RD
J103
J206
OFF
[ON]
J209
J210
TR
J207
J208
RS
DP524 MOTHERBOARD
3-4
MAIN
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).
Request to Send J207 & J208 / Terminal Ready J209 & J210 [on]
Handshake signals "RS" and "TR" can be turned on or off, depending on the
application. The default settings for these signals is "on."
3.4.2 Signal Ground-to-Chassis Link J3 [open]
It is normal practice to connect signal ground to power line ground for many
reasons, including safety. In most systems, minimum induced hum is obtained when
this connection is made at one and only one piece of equipment in the audio chain.
To minimize the addition of circulating ground currents in a particular installation,
the default setting is for this jumper link to be open. Note that there is always a 1k
ohm resistor across the link so that the audio ground is never totally isolated from
the chassis ground. To connect audio ground directly to chassis ground in the
DP524, move jumper J3 to the closed position (move jumper towards the front of
the unit).
CAUTION The chassis is always connected to the ground pin of the power line cord. For safety
reasons this ground wire MUST NEVER be disconnected.
3.5 Configuring the Rear Panel DIP Switch S101
The Model DP524 includes certain user-selectable options that are configured by
means of a rear panel DIP switch, S101. Some of them should be configured prior
to first use. Others can be changed as operational needs dictate (See also Section 5,
Operation).
The default settings (delivered from the factory) are shown in brackets in the table
below. Before installing the unit, be sure to verify that the switch positions are in
their desired positions. Explanations follow below.
S101 Switch No. Function Up (On) Down (Off)
1 Test Tone Tone on [Normal]
2 Download/Normal Download [Normal]
3 AES/EBU / S/PDIF [AES/EBU] S/PDIF
4 Command/Aux data mode Command mode [Aux Data mode]
5 Baud rate select 1 See below [See below]
6 Baud rate select 2 See below [See below]
7 Test Tone sample rate 1 See below [See below]
8 Test Tone sample rate 2 See below [See below]
3-5
MAIN
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. 1, 7 & 8 - Test Tone [down]
Switch position S101-1 activates the built-in test tone generator at a nominal -18dB
amplitude relative to both digital and analog full scale. The decoded signal is
interrupted when the test tone is activated. Switch positions S101-7 and S101-8 are
typically chosen to correspond to the incoming sample rate, so that both the test
tone and audio output have the same sample rate. The frequency of the test tone
varies somewhat with the sample rate chosen.
Output Sample
Frequency S101-7 S101-8
Rate
48 kHz 1125 Hz [Down] [Down]
44.1 kHz 1033 Hz Down Up
32 kHz 750 Hz Up Down
Illegal Undefined Up Up
Keep S101-1 in the Normal position when not using this feature.
3.5.2 Switch nos. 2, 5 & 6 Software Download [down]
The RS-232 port (J105) can be used for upgrading of the audio coding algorithm
software.
When invoking the download mode, the baud rate selection switches S101-5 and
S101-6 must also be set, depending on the data transfer rate, per the following
table:
Baud Rate S101-5 S101-6
9,600 [Down] [Down]
19,200 Down Up
38,400 Up Down
See Section 5.4 for download instructions. RS-232 interface specifications are
located in Section 6.1.
Keep S101-2 in the Normal position when not using this feature.
3-6
MAIN
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 S101-3
S/PDIF Down
AES/EBU [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.
Note Digital audio output is fed to both the BNC and the XLR connectors of the rear of the unit
simultaneously. However, only one of the connectors may be used at a time; otherwise the unit will be
excessively loaded, and may malfunction.
3.5.4 Switch nos. 4, 5 & 6 - Command/Aux Data [down]
Switch position determines whether the RS-232 port J105 is configured as an Aux
Data output or is used for remote control.
Mode S101-4
Aux Data [Down]
Command Up
In Aux Data mode, the unit will send out serial data contained in the digital audio
data stream at the baud rate defined by the table below.
In Command Mode, the unit responds to a series of five byte packets at a fixed rate
of 9600 baud. See Section 6.3 for further details.
Switch 5 & 6 sets the baud rate for the AC-3 Aux Data channel as follows:
Baud Rate (AC-3) S101-5 S101-6
0 [Down] [Down]
1200 Down Up
2400 Up Down
9600 Up Up
Notes No handshaking is used in Aux Data mode.
AC-2 Mono supports an aux data rate of 600 Baud only; AC-2 Stereo supports 1200 Baud only. The position
of these switches is therefore immaterial.
4.1 Mounting
MAIN
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). Note that the ambient temperature inside a poorly-ventilated rack may be
considerably higher than that in the room.
4.2 Audio Connections
SECTION 4
INSTALLATION
4.2.1 S/PDIF Output - J102
Connect this output to the S/PDIF digital audio input of the equipment following
the DP524 using 75 ohm shielded cable.
Note To maintain better mechanical and electrical integrity, the rear panel connector on the DP524 is a
BNC female connector rather than the typical phono jack normally encountered in S/PDIF installations.
4.2.2 AES/EBU Output - J101
Alternatively, connect this output to the AES/EBU digital audio input of the
equipment following the DP524 using 110 ohm balanced and shielded cable.
Note The AES/EBU and S/PDIF outputs cannot be used simultaneously. If connections are made to both
outputs, neither will function properly.
4.2.3 Analog Outputs - J106/7
Alternatively, if using the Analog outputs, make connections at the DP524 analog
outputs J106 (Ch. A) and/or J107 (Ch. B) which are provided with industrystandard XLR female connectors.
Note When operating in single channel audio coding modes, only audio from Channel A is used.
AES and IEC convention calls for XLR pin 2 to be “high/hot” and pin 3 to be
“low/cold”. In the interests of maintaining international standardization, we suggest
that the AES and IEC recommendations be followed.
4-2
MAIN
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. Note that both audio pins of the XLRs (pins 2 and
3) must be connected; neither may be left open.
4.3 Data, Status, and Remote Control Connections
Note Serial Command control can also be implemented in specialized applications by means of the RS-
232 port, J105). See Section 6.3.
4.3.1 Encoded Data In & Timing - J103
Make the Encoded Data In and Timing connections to the 37-pin D-connector
J103. This connector follows the interface specifications of EIA standard RS-449
in the type DT mode (data and timing signals only). Under RS-449, the DP524 is
categorized as data terminal equipment (DTE), and is typically connected to data
circuit-terminating equipment (DCE) such as telecommunications or RF modems.
Detailed information on the RS-449 interface is provided in Section 6.2.
System Clock Requirements
A phase-locked loop (PLL) generates all sample and data timing. The PLL locks to
an external data clock at the coder data rate, and a crystal-based oscillator is used
within the PLL to minimize timing jitter in the sampled audio data. The frequency
locking range of the loop is ± 100 ppm. As an example, a 192kHz data rate would
require a stable external data clock in the range from 191.9808 kHz to 192.0192
kHz, with a 50% duty cycle per RS-449.
4.3.2 RS-232 (J105)
The RS-232 connection can be used for three purposes:
a. As an input for downloading software upgrades; see Section 5.4.
b. As an I/O port for remote commands. See Section 8.
c. As an output for auxiliary data sent from the encoder and embedded
in the digital audio data stream. RS-232 interface data can be found in
Section 7.1. The Command/Aux data switch (S101-4) should be in the
Down position. The communications protocol for command mode is fixed at
1 stop bit, no parity and the baud rate is set as follows:
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Baud Rate S101-5 S101-6
0 Down Down
1200 Down Up
2400 Up Down
9600 Up 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.
By taking pin 20 of the J104 to +5V, Download is enabled.
The front panel indicators Fault, Test and Mute are reflected on pins 21, 22 and 23
respectively of J104. A low level (<0.5V) represents the inactive condition. A high
level (>4.5V) represents an active condition.
Pins 14-18 and 25 are digital ground points.
MAIN
Once the DP524 is installed and operational, no user-intervention is required. In
MAIN
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. Upon powerup of the DP524, the internal processor performs a diagnostic check of all memory
locations and verifies that processor clock signals are active. Failure of any of these
tests is indicated by the illumination of this LED. Memory or processor failure
during operation will result in a similar display.
SECTION 5
OPERATION
Test
The yellow Test LED indicates that the Test Tone Generator has been activated
(position 1 of rear panel DIP Switch S101 is up).
Mute
The red Mute LED indicates that the unit is not currently able to recover valid
audio. This may because the incoming data rate is outside the lock range of the
internal phase lock loop or because no valid data is being fed into the unit.
48k
The green 48k LED indicates that the unit is currently locked to the incoming data
stream and is recovering valid audio at 48 kHz sample rate.
44.1k
The green 44.1k LED indicates that the unit is currently locked to the incoming
data stream and is recovering valid audio at 44.1 kHz sample rate.
32k
The green 32k LED indicates that the unit is currently locked to the incoming data
stream and is recovering valid audio at 32 kHz sample rate.
Signal Presence A & B
These two green LEDs indicate that audio is present on the analog outputs at a
level greater than approximately-60dB Full Scale.
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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.
The actual frequency of the tone is dependent upon sample rate (see section 3.5.1).
5.4 Software Downloading Procedure
In the event that a software upgrade is required, the RS-232 (J105) may be used to
download the appropriate files and reprogram the EEPROM residing in the DP524.
When this method of upgrade is desired, the necessary files will be supplied in IBM
PC compatible format. The downloading procedure is described below.
Remove all connectors to the DP524 except for the mains power.
Connect rear panel connector J105 to a standard PC serial port.
Note the position of S101-5 and S101-6. They must be restored to this
position when the software downloading is complete.
Set the baud rate select switches S101-5 and S101-6 as desired, according
to the table below:
Baud Rate S101-5 S101-6
9600 Down Down
19200 Down Up
38400 Up Down
Set rear panel switch S101-2 to the up position. As soon as this is done the
Front panel LEDs Mute, 48k, 44.1k and 32k will all be illuminated. During
the download sequence the Test LED will flash.
Software upgrades are supplied by Dolby Laboratories and include complete
instructions relating to the download procedure.
After the unit has been upgraded, move switch S101-2 back to its down
position. The unit will then reboot and begin running the new code.
Return switches S101-5 and S101-6 to their original positions.
INTERFACE SPECIFICATION AND DESCRIPTION
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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 -
SECTION 6
S/PDIF Digital Audio Output,
BNC-type connector, 0.5V p-p typical, 75 ohms.
Encoded Data In and Timing,
Pin Connection Pin Connection
1 Shield (chassis ground)
2 NC (no connection) 20 NC
3NC 21NC
4NC 22NC
5NC 23NC
6 RD + (receive data +) 24 RD – (receive data –)
7NC 25NC
8 RT + (receive timing +) 26 RT – (receive timing –)
9NC 27NC
10 NC 28 NC
11 NC 29 NC
12 NC 30 NC
13 NC 31 NC
14 NC 32 NC
15 NC 33 NC
16 NC 34 NC
17 NC 35 NC
18 NC 36 NC
19 SG (signal ground) 37 NC
J102
, 37-pin D-connector :
J103
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Status / Control,
Pin Connection Comments
1 NC Do Not Connect
2 NC Do Not Connect
3 NC Do Not Connect
4 NC Do Not Connect
5 NC Do Not Connect
6 NC Do Not Connect
7 NC Do Not Connect
8 NC Do Not Connect
9 NC Do Not Connect
10
11 NC Do Not Connect
12 NC Do Not Connect
13 VREF Logic Level Reference (+5V)
14 DGND Digital ground
15 DGND Digital ground
16 DGND Digital ground
17 DGND Digital ground
18 DGND Digital ground
19 TEST IN Input, Enable Test Tone
20 DOWNLOAD Input, Enable Software Download
21 FAULT Output, System Failure
22 TEST OUT Output, Test Mode
23 MUTE Output, Decoder Muted
24 NC Do Not Connect (start -)
25 DGND Digital ground
NC
, 25-pin D-connector:
J104
Do Not Connect
RS-232 Port,
Pin Connection Comments
1 DCD direct connection to DTR, DSR, and CTS
2 RX asynchronous data out
3 TX asynchronous data in
4 DTR direct connection to DCD, DSR, and CTS
5 Ground
6 DSR direct connection to DCD, DTR, and CTS
7NC
8 CTS direct connection to DCD, DTR, and DSR
9NC
J105
Analog Audio Input,
XLR-type connectors
Pin Connection
1 Analog signal ground
2 Analog Audio +
3 Analog Audio -
J106
&
J107
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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. The Model DP524 is
configured as data terminal equipment (DTE), and are typically connected to data
circuit-terminating equipment (DCE) such as RF modems. The DP524 decoder
receives a data clock from a DCE device on the receive timing (RT) pins, and
receives data on the receive data (RD) pins. The internal timing and sample clocks
of the DP524 are phase-locked to ST and RT, respectively. In addition to these
differential signals, the connector also provides pins for signal and chassis ground;
connector pinout is given in the section above. No other RS-449 signals are
supported in these units.
6.2.2 Interface Timing
A “mark,” or “off” state is said to exist when the “+” side of a signal is at a lower
potential than the corresponding “-” side. A “space,” or “on” state exists when the
opposite condition is true. The following timing diagram shows the relationship
between clock and signal lines:
TT
ST
SD
RT
on
off
RD
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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. This cable also connects the SD outputs of the DP523 to the RD inputs of
the DP524, and connects the signal grounds (SG) of the two units. The DP523 end
of the cable should be labeled “Encoder” and the DP524 end should be labeled
“Decoder”. The cable connections are shown below:
DP523 Encoder DP524 Decoder
6.3 Serial Control
MAIN
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.
The unit expects to receive a five byte sequence and responds in one of the
following ways:
x If the command sequence is not expecting to return a value (as in the case
of Enable Test Tone) then successful receipt of the command is responded
with a single ASCII character '*'.
x If the command sequence is not received correctly (for example the stop
byte $FD is corrupted) then the unit responds with a single ASCII character
'?'.
6-5
x If the command is expecting a reply (as in the case of Return Status) then
that status byte is returned.
The data sequence is as follows ($ prefix denotes hexadecimal notation):
6.3.1 System related commands
The following commands are system commands and will be responded to
regardless of the algorithm currently loaded.
Command $14: Enable/Disable Test Tone
$FB $20 $14 data $FD
Where data is as follows:
B7 B6 B5 B4 B3 B2 B1 B0
Enable0 0 0SR2SR10 0
Enable, SR2 and SR1 are defined as follows:
SR1 SR2 Enable Comment
X X 0 Test Tone Disabled
0 0 1 48kHz Sample Rate, 1125Hz Tone
1 0 1 44.1Khz Sample Rate, 1033Hz Tone
0 1 1 32kHz Sample Rate, 750Hz Tone
1 1 1 Illegal
Note:
This command will only be accepted if the DIP switch controlling the Test Tone
(S101-1) is set for normal operation. If S101-1 is set active, this command will
respond with a '?' instead of '*'.
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Command $18: Return System Status
$FB $20 $18 0 $FD
The unit returns the following byte:
B7 B6 B5 B4 B3 B2 B1 B0
0 Dr_lock Sr_lock Test 48kHz 44.1kHz 32kHz 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.
Command $19: Return System Contents
$FB $20 $19 Index $FD
This command returns a collection of strings of characters which describe the
contents of the current firmware revision including the revision of the system
control software and all of the loaded algorithms.
The 'Index' byte starts at 0 and is incremented until the unit returns a zero. On each
successive call, the unit will return the following ASCII character in the associated
null terminated string. A Linefeed character (decimal 10) separates each string.
Command $1A: Return Current Algorithm
$FB $20 $1A Index $FD
The 'Index' byte starts at 0 and is incremented until the unit returns a zero. On each
successive call, the unit will return the following ASCII character in the associated
null terminated string.
This command returns the name of the current decoder algorithm which is loaded.
Command $1B: Return Current bitrate.
$FB $20 $1B 0 $FD
This command returns a byte which describes the current decoder bit-rate. NOTE:
This data is only valid if the Dr_lock bit in 'Return System Status' byte is true.
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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.
Otherwise the returned data is as follows:
B7 B6 B5 B4 B3 B2 B1 B0
0000BR3BR2BR1BR0
BR3 BR2 BR1 BR0 Bit Rate (total)
000140k bits/sec
001048k bits/sec
001156k bits/sec
010064k bits/sec
010180k bits/sec
011096k bits/sec
0111112k bits/sec
1000128k bits/sec
1001160k bits/sec
1010192k bits/sec
1011224k bits/sec
1100256k bits/sec
1101320k bits/sec
1110384k bits/sec
1111448k bits/sec
6.3.2 AC-3 Related commands
The following commands are only applicable to the AC-3 algorithm. If they are
issued when any other algorithm has been loaded, they will be ignored.
Command $40: High Level Dynamic Range control
$FB $20 $40 data $FD
Where data is a byte of value 0..$ff.
0 corresponds to a fractional control value of 0.0.
$ff correspods to a fractional control value of 0.996.
Command $41: Low Level Dynam ic Range control
$FB $20 $41 data $FD
Where data is a byte of value 0..$ff.
0 corresponds to a fractional control value of 0.0.
$ff correspods to a fractional control value of 0.996.
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MAIN
Command $42: Set Compression mode
$FB $20 $42 data $FD
Where data is as follows:
B7 B6 B5 B4 B3 B2 B1 B0
000000C1C0
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
SECTION 7
MAIN
DP524 SPECIFICATION
Specifications
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.
Distortion
AC-2 Less than 0.1 % at 1 kHz.
AC-3 Less than 0.005 %, 20 Hz - algorithm upper limit.
Dynamic Range
Greater than 108 dB (encode/decode, digital I/O).
Greater than 100 dB (encode/decode, analog I/O).
Crosstalk
Less than - 120 dB @ 1 kHz
Level Stability
AC-2 Better than 0.2 dB.
AC-3 Better than 0.01 dB.
1
2
Less than 0.2 %, 20 Hz - algorithm upper limit.
Audio Coding Method
Dolby AC-2 or AC-3
3
Time Delay
Varies with algorithm. Contact Dolby Laboratories.
External Timing
External clock range: ±100 ppm of total data rate; RS-422 input (balanced voltage digital
interface, 50% D.C. per RS-449 specification).
Audio Sample Rate
32 kHz, 44.1 kHz or 48 kHz (AC-3).
48kHz (AC-2).
Test Tone Generator
Digital equivalent of approximately 1 kHz sine wave at. Actual frequency dependent on output
sample rate. Level is -18dB Full Scale.
Analog Audio Output
3-pin XLR-type male. Active balanced output, 22 ohms, adjustable up to +24dbu Full Scale.
1
Subject to change without notice.
2
Measured with an Audio Precision System One.
3
Patents Pending Worldwide.
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Digital Audio Outputs
AES/EBU, 3-pin XLR-type, male, balanced , 110 ohms ±5%, 5V
S/PDIF, BNC female connector, unbalanced, 75 ohms ±5%, 0.5V
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.
S101-1 Enable Internal Test Tone Generator
S101-2 Normal/Download Control
S101-3 S/PDIF / AES/EBU select
S101-4 Select Command/Data mode
S101-5 Baud Rate Select 1
S101-6 Baud Rate Select 2
S101-7 Tone sample rate 1
S101-8 Tone sample rate 2
Rear Panel Controls
Output Level trim, 10-turn, each channel is adjustable from -10 to +24dBm Full Scale.
pp nominal.
pp nominal.
Front Panel Indicators
Signal Presence, CH A
Green indicates that a signal greater than -60dB FS is present on the channel A output.
Signal Presence, CH B
Green indicates that a signal greater than -60dB FS is present on the channel B output.
32kHz
Green indicates that unit is locked to the incoming bitrate and that the sample rate of the
incoming data is 32kHz.
44.1kHz
Green indicates that unit is locked to the incoming bitrate and that the sample rate of the
incoming data is 44.1kHz.
48kHz
Green indicates that unit is locked to the incoming bitrate and that the sample rate of the
incoming data is 48kHz.
Mute
Red LED indicates that there is no incoming clock or the bit stream does not contain
valid audio.
Test
Yellow warns that the Test Tone Generator is selected.
Fault
Red indicates a power supply or processor/memory failure.
Remote Control Inputs
Enable Test Tone
Software Download
Status Outputs
Fault output
Test output
Mute output
General
MAIN
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.
Warranty
1-year limited, parts and labor.
7-3
Non-operating (Storage): -40 oC to 85 oC.
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