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1. Encoder DSPs Broadcast Data Port J4 RS 422 Controller Relay Contacts gt RS 232 RS 485 Async Data User Data gt Remote Control Figure 2 19 F098 ISO MPEG Layer II IIA Codec DAC700 Block Diagram for LB 1 Functional Description and Theory of Operation 2 21 LB 2 Normal Operation In LB 2 the data is received from the analog input port as shown in Figure 2 20 encoded and then sent out the broadcast data port From the encoder data is also sent to the decoder This mode is primarily used for normal system operation Analo Input Port J2 Digital Audio Analog Output Port J1 Sensor Input Closure Contacts RS 232 pla User Data Figure 2 20 Channel A g Channel B Channel A Channel B 16 8 LB 2 Path Control Encoder Controller Relay Contacts Broadcast Data Port J4 RS 422 Async Data gt RS 232 RS 485 gt Remote Control F099 ISO MPEG Layer II IIA Codec DAC700 Block Diagram for LB 2 2 22 Functional Description and Theory of Operation Overview ISO MPEG Layer II IIA Functional Description This section is reprinted in part with the permission of Corporate Computer Systems Inc CCS The DAC700 uses the ISO MPEG Layer IIIA compression algorithm As the most tested documented and reviewed audio compression algorithm in the world ISO MPEG Laye
2. The major components that make up a system For example the DAC700 and CM701 are the uplink modulator subsystem The ABR200 with an LNB and dish with IFL cable are the receive site downlink subsystem To switch from one operating unit to another unit with the same configuration Time Division Multiplexing Transmit Timing Clock TTL stands for Transistor Transistor Logic and references on and off levels A one equals a high 5 volts Transmit Transmit Clock Universal Asynchronous Receiver Transmitter Underwriters Laboratories An unprotected system does not have the built in capability to switch to a spare piece of equipment when a fault occurs Uninterruptible Power Supply Glossary 5 User Data Blocks VDE XCO User data blocks are one of three types of ancillary data that can be processed by the DAC700 User data blocks are originated by the user and input into the DAC700 for broadcast transmission to all receivers Of the three types of data user data blocks have the lowest priority volts Verband Deutscher Elektrotechniker watts Crystal Controlled Oscillator Glossary Index A ABR200 75 receiver data block length 2 11 transmission channel signal format 2 5 Acquisition range 2 5 AES EBU definition 3 3 Analog input port audio input interfaces 2 9 description 3 3 interface pinout B 2 maximum input 3 3 port number A 3 Analog output phase alignment 3 3 Analog output port 2 10 decoder interfa
3. The packet to issue an EM query command is constructed as shown in Table 5 1 Table 5 1 Packet Protocol EM Query Command Le Byte Device Control 9 Checksu Byte Description STX Count Address Byte E M space m ETX Before Parity 024 OA 21H 01H 454 4D4 20H 3Fy 134 03H After Odd Parity 024 8Ap A1 H 01 H 4544 CDy 204 BFy 13H 83H ComStream Packet Protocol Communications Modes Two communications modes are supported by ComStream packet protocol a One way communication consisting of controller to slave transmission with no slave response requested a Two way communications consisting of controller to slave transmission with a slave to controller acknowledgment response The controller may indicate which communications mode is to be followed on a packet by packet basis by transmitting the appropriate control byte to the slave One way communication mode In one way communication information is sent one way only from the controller to the slave In this mode the controller receives no information from the slave and is operating in an open loop mode In this mode the slave does not respond to the controller nor send any type of messages informing the controller of commands received nonexecuted commands or error conditions Two way communication mode Operating in a two way communication mode the controller receives a response packet from the slave for every packet transmitted The data portion of the slave response packet depen
4. 12 13 14 15 S16 OPTOCOM 12 V SG RC1A RC1B RC2A RC2B Description Sensor Input 1 opto cathode Sensor Input 2 opto cathode Sensor Input 3 opto cathode Sensor Input 4 opto cathode Sensor Input 5 opto cathode Sensor Input 6 opt cathode Sensor Input 7 opto cathode Sensor Input 8 opto cathode Sensor Input 9 opto cathode Sensor Input 10 opto cathode Sensor Input 11 opto cathode Sensor Input 12 opto cathode Sensor Input 13 opto cathode Sensor Input 15 opto cathode ae SS we e SU Sensor Input 14 opto cathode Sensor Input 16 opto cathode Opto Common anode 12 V thru 220 ohm resistor Signal Ground Relay Closure Contact 1A Relay Closure Contact 1B Relay Closure Contact 2A Relay Closure Contact 2B Interface Pinouts B 7 Table B 7 DB 37 Female Connector Pinouts continued Pin 24 25 26 27 28 29 30 31 32 33 34 35 36 37 S O O O O O O O O O O O O OO Name RC3A RC3B RC4A RC4B RC5A RC5B RC6A RC6B RC7A RC7B RC8A RC8B SG SG Description Relay Closure Contact 3A Relay Closure Contact 3B Relay Closure Contact 4A Relay Closure Contact 4B Relay Closure Contact 5A Relay Closure Contact 5B Relay Closure Contact 6A Relay Closure Contact 6B Relay Closure Contact 7A Relay Closure Contact 7B Relay Closure Contact 8A Relay Closure Contact 8B Signal Ground Signal Ground B 8 Interface Pinouts
5. A positive differential at the RCV outputs Vrev gt Vrev also known as a space is intended as a TTL 0 which is considered to be a start bit per EIA specifications A positive differential at the Xmit inputs Vxmit gt Vxmit also known as a space will be interpreted as a TTL 0 which is considered to be a start bit per EIA specifications ComStream Packet Protocol 5 7 COMSTREAM A Spar Company 5 8 ComStream Packet Protocol Overview Maintenance Maintenance and Troubleshooting This chapter provides information about the maintenance of the DAC700 This chapter also provides an alphabetical listing of the following a Key performance monitoring and maintenance commands a Fault conditions Status fault indicator lights These listings provide a description of each command and fault condition Other maintenance topics include cables and connectors The last section of this chapter presents information that can help troubleshoot problems that may occur with the DAC700 The DAC700 does not require scheduled or preventive maintenance The unit has no internal or external configuration switches jumpers or straps that require setting by the technician or operator Cleaning the DAC700 The DAC700 may be cleaned if desired Before cleaning the DAC700 be sure to unplug it from the wall outlet Do not use water or any type of abrasive pad scouring powders liquid cleansers aerosol cleansers or solvents s
6. 1 slave is required to acknowledge receipt of packet e Bits 1 6 are always 0 o For slave to controller communications e Bits 0 5 are always 0 e Bit 6 is always 1 a Data Used to transfer information from one device to another such as commands from the controller to the slave or response information from the slave to the controller The format of this data varies depending on message content a Checksum Verifies the integrity of the characters contained within a message The checksum is computed as the sum modulo 128 of packet bytes beginning with the device address byte and ending with the last byte of the data field a ETX Signifies the end of a packet Its ASCII value is ETX 03 All controller or slave generated packets have a Minimum length of six bytes Minimum packet format omits the data field and consists of STX Byte Count Address Control Checksum ETX a Maximum length of 127 bytes including delimiters and checksum All packets with a length exceeding 127 bytes or that do not meet the prescribed format are discarded ComStream Packet Protocol Address Selection To select the remote address of a DAC700 for ComStream packet protocol mode use the M amp C port to change the packet address with the RA command For more information on the Packet Address command refer to the chapter on remote monitor and control operation ComStream Packet Protocol 5 3 Packet Protocol Command Structure Extend
7. Figure 2 15 Figure 2 16 Figure 2 17 Figure 2 18 Figure 2 19 Figure 2 20 Figure 3 1 Figure 5 1 Figure B 1 Figure B 2 Figure B 3 Figure B 4 Figure B 5 Figure B 6 Figure B 7 Single Channel to Multipoint Audio Data Satellite Network 1 2 Multichannel to Multipoint Audio Data Satellite Network 1 3 DAC700 Audio Codec Mux Unit 1 4 DAC700 Front Panel 2 2 DAC700 Rear Panel 2 2 DAC700 Front Panel Indicators 2 3 Multichannel Single Transponder System 2 4 DAC700 Channel Format 2 5 DAC700 Functional Block Diagram 2 8 Audio Input Interfaces 2 9 Audio Output Interfaces 2 10 User Data Processing 2 12 Data Passthrough Processing 2 13 Monitor and Control Processing 2 14 Contact Mapping Diagram 2 15 Clock Generator 2 17 TxCLK Internal Timing PLL 2 18 Send Timing 2 18 Receive Timing 2 19 AES EBU Timing Input 2 19 ISO MPEG Layer IIIA Codec DAC700 Block Diagram for LB 0 2 20 ISO MPEG Layer IIIA Codec DAC700 Block Diagram for LB 1 2 21 ISO MPEG Layer IIIA Codec DAC700 Block Diagram for LB 2 2 22 DAC700 Rear Panel Connectors 3 3 Packet Format 5 2 DB 9 Male Connector B 1 DB 9 Female Connector B 2 DB 15 Female Connector B 3 DB 15 Female RS 422 Connector B 4 DB 9 Female RS 232 Connector B 5 DB 9 Female RS 232 or RS 485 Connector B 6 DB 37 Female Connector B 7 Contents vii Tables Table 2 1 Table 2 2 Table 2 1 1 Table 2 1 2 Table 3 1 Table 4 1 Table 4 2 Table 4 3 Table 5 1 Table 5 2 Table 6 1
8. Relay control port description 3 5 function 2 15 Relay control port A 4 interface pinout B 7 port number A 3 Remote monitor and control commands 4 4 descriptions 4 4 error codes 4 2 escape character 4 1 summary 4 2 syntax 4 1 Remote operations activate deactivate relays temporarily 4 9 ancillary data rate set or read 4 5 audio bandwidth set or read 4 4 audio muting set or read 4 15 audio test tone set or read 4 6 channel ID number set or read 4 7 clear fault 4 7 compression algorithm set or read 4 6 control port configuration set or read 4 16 current preset set or read 4 19 data block length set or read 4 7 data port 2 configuration set or read 4 19 decoder ancillary data rate set or read 4 11 display accumulated faults 4 13 display real time faults 4 22 encoder mode set or read 4 24 mux demux operating mode set or read 4 12 network ID number set or read 4 16 passthrough mode set or read 4 20 preset definition set or read 4 17 preset mode set or read 4 18 protection mode set or read 4 23 query physical state of relay contacts 4 9 receive channel rate set or read 4 21 relay input port configuration set or read 4 27 2 Index remote port address set or read 4 20 remote port configuration set or read 4 20 reset volatile parameters 4 21 sense of audio channel output set or read 4 15 set position of relay closures 4 10 transmit timing mode set or read 4 24 user data
9. 02 95 Initial release Rev B 05 95 All chapters updated references to ISO MPEG Layer II IIA added new section Rev C 08 95 Updated notice page to include CCS copyright notice Rev D 11 95 Command set updates Rev E 07 98 Updated ComStream s address and Customer Service phone numbers removed CPN and revision information from body pages TRevision Ais always the first official release to ComStream customers We hope this guide provides all of the information and instructions you need to operate the DAC700 Codec Multiplexer However in the event that you need further assistance or if problems are encountered ComStream has set up a Customer Support Line for your use Please feel free to contact ComStream Customer Support located in the United States by phone or fax at the following numbers a Phone 619 657 5454 toll free 888 559 0831 Monday through Friday 8 00 a m to 5 00 p m Pacific time Fax 619 657 5455 Preface xiii Safety Precautions Carefully read and follow all safety use and operating instructions before operating the DAC700 Codec Multiplexer Heed all warnings and cautions contained in this guide Retain these instructions for future reference Follow Startup Procedure Do not plug in the DAC700 Codec Multiplexer until you have connected the system and read the chapter on installation and initial startup Provide A Safe Location Place the DAC700 Codec Multiplexer in a rack or on a stable surfa
10. 11 data rates 3 4 description 3 4 interface pinout B 4 network data interface 2 10 port number A 3 timing sources 2 13 2 17 C Cables checking for damage 6 6 Channel ID defining channel ID numbers 3 11 proper signal discrimination 2 5 Cleaning 6 1 Clock generator audio input and output interfaces 2 10 description 2 17 CM701 modem 2 10 2 16 ComStream packet protocol address selection 5 3 command execution 5 5 command structure 5 4 communication modes 5 6 one way 5 6 extended addressing 5 4 format 5 2 byte count 5 2 checksum 5 3 data 5 3 device address 5 2 ETX 5 3 minimum length 5 3 packets that do not meet prescribed format 5 3 STX 5 2 interface 5 1 messaging 5 1 pinout specifications 5 7 specifications 5 7 Connectors checking for damage 6 5 D DAC700 1 1 1 4 Data multiplexer 2 9 2 13 2 15 2 16 Data port A 4 channel 1 2 11 3 4 channel 2 2 12 3 4 A 4 data rates 3 4 description 3 4 implementation 2 13 Index 1 interface 2 11 interface pinout B 5 port number A 3 Decoder processor 2 16 Diagnostics A 3 Duplex mode 4 12 Dynamic bit allocation 2 1 2 E Electromagnetic interference EMI 3 2 Emission standards compliance 3 3 Encoder processor 2 16 Environmental specifications A 5 F Fault conditions audio overload 6 4 6 7 decoder DSP alarm 6 7 decoder not framed 6 4 6 7 encoder DSP alarm 6 7 network channel ID fault 6 4 Rx PLL unlock 6 4 6 7 Tx PLL unlock 6 4 6 7 Fields of use 2 1 3 com
11. 6 2 Maintenance and Troubleshooting Table 6 1 Key Performance Montoring and Maintenance Commands continued Command Function Description LB Loopback This command can be used to isolate system faults to a failure of the DAC700 unit or of another unit in the system such as the modem or ABR receiver Three loopback modes are available External Baseband Input Loopback Operation LB 0 In external baseband input operation an ISO MPEG Layer II IIA stream from an external source is brought in through the broadcast data port decoded and sent out the audio output ports An independent ISO MPEG Layer II IIA stream can also be sent out the broadcast data port This mode can be used to monitor the uplink since you are using the DAC700 as a decoder only External baseband input audio means that the onboard decoder and the DAC are operating correctly Abnormal muted or absent loopback audio means that either the decoder or DAC is not operating correctly or is improperly configured PCM Loopback Operation LB 1 In PCM loopback operation analog audio is converted into 16 bit linear PCM data and transferred directly from the ADC output to the DAC input bypassing the DSP encoder decoder This mode can be used to verify the ADC performance while bypassing the algorithm Normal PCM loopback audio means that the audio transmit and receive converters are operating correctly Abnormal muted or absent loopback audio means the ADC the DAC or bot
12. Bandwidth D Additional Information The selected bandwidth is dependent on transmission rate TD and operating mode TM For the relationship between bandwidth transmission rate and operating mode see the appendix on technical specifications and port information Remote Monitor and Control Operation AG AM Aggregate Encoder Decoder Ancillary Data Rate Use this command to set or read the encoder decoder ancillary data rate Syntax AG lt baud gt lt parity gt lt data_bits gt lt stop_bits gt AG Parameters Valid lt parameters gt and their values are as follows a lt baud gt 1200 2400 4800 9600 38400 a lt parity gt O E N odd even none a data_bits 8 a lt stop_bits gt 2 a Defaults 38400 N 8 2 Additional Information The AG parameter data and stop bits must be set to 8 and 2 respectively Alarm Mask Use this command to set or read the alarm relay mask Syntax AM lt parameter gt AM Parameters lt parameter gt is the decimal number that represents the bit map of the faults to be monitored by the status relay as shown below Fault Number Fault Condition Decimal Weight 1 Tx PLL not locked 1 2 Rx PLL not locked 2 3 Decoder not framed out of sync 4 4 Audio overload left channel 8 5 Audio overload right channel 16 6 Network or channel ID fault 32 The default is 255 Remote Monitor and Control Operation 4 5 AS AT Algorithm Select Use this command
13. PCM Loopback Operation LB1 PLL Point to Point PPL PROM Protected QPSK RAM Redundancy Protection Relay Blocks RF The DAC700 passthrough mode is a selectable configuration for transferring user data Passthrough mode allows the user to transfer preformatted data Preformatting the data minimizes the overhead of the onboard multiplexer The passthrough mode can be selected at any time independent of user data relay control messages or control channel information Personal Computer Pulse Code Modulation In PCM loopback operation the data is looped from the output ADC through the DAC bypassing the DSP encoder decoder This mode can be used to verify the ADC performance while bypassing the algorithm Phase Lock Loop Communication between two points only Peak Program Level Programmable Read Only Memory A protected system has the built in capability to detect when a fault has occurred in the uplink transmission of one of the channels When a fault is detected the system swaps out the faulty DAC700 CM701 with the channel in the rack referred to as the spare The spare channel also consists of a DAC700 CM701 Using this technique ensures that the rack is always protected unless a fault has previously occurred and the faulty channel has not yet been fixed Quadrature Phase Shift Keying Random Access Memory An optional configuration in which an extra DAC700 serves as a backup to one or more other DAC700
14. PS1 Preset Select Bit 1 5 PS2 Preset Select Bit 2 6 DIGIN AES EBU Digital Audio In 7 O SG Signal Ground 8 O DIGOUT AES EBU Digital Audio Out 9 RST Remote Control Reset short to pin 1 SG 10 O Status Status Closure Contact 2 11 Reserved 12 Reset External Reset 13 O DIGIN AES EBU Digital Audio In 14 O SG Signal Ground 15 O DIGOUT AES EBU Digital Audio Out Interface Pinouts B 3 Broadcast Data Port J4 The pin positions for the broadcast data port connector are given in Figure B 4 OOOOOOOO OOOO F088 Figure B 4 DB 15 Female RS 422 Connector The pinout specifications for the broadcast data port connector are given in Table B 4 Table B 4 DB 15 Female RS 422 Connector Pinouts Pin 1 0 Name Description 1 O FG Frame Ground 2 O TD Transmit Data 3 O TT Terminal Timing 4 RD Receive Data 5 Not used 6 RT Receive Timing 7 ST Send Timing 8 SG Signal Ground 9 O TD Transmit Data 10 O TT Terminal Timing 11 RD Receive Data 12 Not used 13 RT Receive Timing 14 ST Send Timing 15 Not used B 4 Interface Pinouts User Data Port J5 The pin positions for the user data port connector are given in Figure B 5 60000 OOOO F087 Figure B 5 DB 9 Female RS 232 Connector The pinout specifications for the user data port connector are given in Table B 5 Table B 5 DB 9 Female RS 232 Connector Pino
15. The DAC700 has eight possible connections including the power plug on the rear panel The location of these connectors is shown in Figure 3 1 J1 J2 J3 J4 J5 J6 J7 ANALOG OUTPUT ANALOG INPUT AUX AES BROADCAST DATA USER DATA M amp C RELAY CONTROL Figure 3 1 DAC700 Rear Panel Connectors The pinouts for these interfaces are detailed in the appendix on interface pinouts To ensure compliance with emission standards all signal cables connected to the receiver should be shielded The shield must be electrically attached to the mating connector Analog Output The analog output port has two balanced output channels from the decoder one right channel and one left channel Ensure that phase alignment is maintained between studio equipment and the encoder If a phasing error occurs when operating in the joint stereo mode common mode background noise may be accentuated Analog Input This port has two balanced input channels for the encoder one right and one left audio channel The maximum input level before distortion occurs is 18 dBu dBm Above this level the DAC700 hard clips the signal Audio input impedance is configured internally for gt 100 kohm audio input impedance at the factory An optional cable ComStream Part No 05 0548 001 can be used to configure it for 600 ohm balanced operation AUX AES This port provides two digitized AES EBU audio channels an input channel to the encoder and
16. UB lt parameter gt UB Parameters Valid lt parameter gt values specify the value in milliseconds the valid range is 0 to 1000 A value of 0 indicates no time interval and causes the characters to be sent as they are received with one character per packet The default is 500 Example A lt parameter gt of 500 sets the send interval to 500 ms or 0 5 sec Remote Monitor and Control Operation 4 25 UC UT Data Port 1 Configuration User Data Use this command to set or read the user data port configuration Syntax UC lt baud gt lt parity gt lt data_bits gt lt stop_bits gt UC Parameters Valid lt parameters gt are as follows a lt baud gt 0 off 300 1200 2400 4800 9600 a lt parity gt O E N odd even none a lt data_bits gt Tors a lt stop_bits gt lor 2 a Defaults 2400 0 7 1 User Termination The user termination command enables the user to specify an 8 bit character or value which is checked against incoming characters Syntax UT lt parameter gt UT Parameters lt parameter gt is the decimal value of the ASCII character to be used as the termination character The default is 0 Additional Information If the value is less than zero and matches a character then the character is discarded from the input user stream and the current user block is terminated If the character is greater than zero then the termination character is stored in the current block for tr
17. as well as auxiliary information describing bit allocation and scale factors all of which are required by the decoder to reproduce the audio information The scale factors are determined by searching for the maximum sampling value in each subband and quantizing the result using 16 bit sampling The scale factors have a dynamic range of 120 dB which is sufficient for future encoding of quantized Pulse Code Modulation PCM signals using up to 20 bit sampling while still retaining their dynamic range All necessary information is encoded into Musicam frames each of which represents about 24 ms of real time audio 2 1 2 ISO MPEG Layer II IIA Functional Description All of the complex calculations of the ISO MPEG Layer II IIA algorithm are performed by the encoder Decoders are designed to be universal ISO MPEG Layer IIA decoders that correctly decode and play back audio information that has been encoded by a range of ISO MPEG Layer IIIA encoders can be constructed This aspect to the ISO MPEG Layer IIIA algorithm is crucial because it enables refinements in the encoding process to further improve performance without impacting decoders that are already installed Performance Considerations Four fields of use are commonly described in discussing performance considerations Contribution a Distribution a Emission a Commentary Contribution grade is used to describe quality suitable for digital master Its use would be in the tran
18. demultiplexed into user data relay control messages and network control commands and the user data is output via data channel 1 Figure 2 9 illustrates user data processing Encoder Processor Broadcast RS 422 i gt a Data Port Sync Data J4 Including Unit Controller User Data Digitized Audio Transmit Side Digitized Audio RS 422 Broadcast Audio Data Decoder Data P User ree Data Port Decoder Processor i Data J4 DSP 4 User Data 34 pers Out Unit Controller Receive Side F074 Figure 2 9 User Data Processing Data channel 2 Data port channel 2 allows the user to send passthrough data The data rate is programmable and is embedded into the output ancillary data stream The passthrough mode allows the user to transfer preformatted data to minimize the overhead of the onboard multiplexer In this mode an external source such as the ComStream Smart Node performs the formatting normally done internally by the DAC700 The passthrough mode can be selected at any time independent of user data relay control messages or control channel information Passthrough data rates vary from 300 to 9600 bps Passthrough data can be any of the allowable data types for the system that is user data relay control and network control commands It is not recommended to send a block type via data port channel 1 when sending the same block type in the passthrough mode via channel 2 2 12 Functional
19. frequencies and ID numbers it is possible that carriers B and C will be incorrectly received since they are within 600 kHz of each other and do not have unique ID numbers All other carriers will operate properly Functional Description and Theory of Operation DAC700 Major Functional Modules The major functional modules of the DAC700 consist of Audio input interfaces Audio output interfaces Broadcast data interface User data interface Passthrough interface M amp C interface Relay control interface Audio data encoder Audio data decoder Data multiplexer Unit controller Clock generator Power module A brief description of each functional module is provided in the following paragraphs Functional Description and Theory of Operation 2 7 Figure 2 6 is a block diagram of the DAC700 RS 422 Sync Data Analog Audio Out Channel A B Power Audio Sync Dual Mono Joint Stereo Overload Fault User Data Passthrough lt 4 Data Analog to Digital Converter Broadcast i ADC Data J4 AES EBU Interface Data Decoder DSP 4 Digital to Analog e Converter DAC Front Panel Unit Controller 4 Relay Encoder Contacts Decoder Data gt Port J5 Analog Audio In Channel A B Digital Audio gt In Out _ 16 Sensor Inputs Ly 8 Closure Contacts c RS 232 M amp RS 485 Port J6 4 Re
20. interval set or read 4 25 user data port configuration set or read 4 26 RS 232 data interface 2 11 M amp C interface 2 14 RS 485 M amp C interface 2 14 S Satellite broadcast network configurations 1 3 satellite link 1 2 satellite receiver 1 3 satellite transmission uplink station 1 2 subsystems 1 2 Simplex mode 4 12 Site planning 3 1 T Terminal configuration 3 6 installation check 3 5 Timing sources 2 17 selecting a timing source 3 11 Transmission channel signal format 2 4 U Uninterruptible power supply UPS 3 2 Unit controller ancillary data 2 12 audio input 2 9 data 2 11 2 13 data multiplexer 2 16 description 2 16 M amp C 2 14 relay control messages 2 1 timing and timing source selection 2 19 user data 2 16 User data ancillary data multiplexer 2 16 data channel 1 transmit side 2 11 data channel 2 receive side 2 13 data interface 2 11 Passthrough data data channel 2 receive side 2 13 passthrough data 2 12 passthrough mode 2 12 priority 2 11 processing 2 12 rate 2 11 User data configuration configure channel 1 3 8 set termination character 3 9 set time or send interval 3 8 User relay configuration configure relay input port 3 11 defining message interval 3 11 mapping relays 3 10 setting contact sense polarity 3 10 Index COMSTREAM A Spar Company Index
21. is very subjective The guideline given in this guide is a recommendation only To configure encoder decoder ancillary data 1 Set the ancillary data rate for the encoder decoder The command format is AG baud parity data_bits stop_bits 2 Set the mux demux mode The command format is DM 0 for simplex mode DM 1 for full duplex mode For a definition of simplex and duplex modes refer to the chapter on remote monitor and control operation User Relay Configuration Configure user relays to provide control of cueing or event operations for a studio console event sequencer or ABR receiver For example user relays can turn specific receivers on at a set time Use the following steps to configure these relays 1 Set the contact sense polarity for the eight relay channels The command syntax is CS relay_1l relay_2 relay_3 relay_4 relay_5 relay_6 relay_7 relay_8 For each instance of relay substitute 0 relay normally open 1 relay normally closed This is a DAC700 decoder function only 2 Map transmit relays to receive relays The command syntax is CM relay_1l relay_2 relay_3 relay_4 relay_5 relay_6 relay_7 relay_8 This is a DAC700 decoder function only 3 10 Installation and Initial Startup 3 Define the relay message interval The command syntax is RM interval Interval is the time between relay control message updates 4 Configure the relay input port The com
22. mode RA Remote Port Address Use this command to set or read the remote port address for the unit Syntax RA lt parameter gt RA Parameters The valid lt parameter gt address range is 1 through 31 The default is 31 RC Remote Control Port Configuration RS 485 Use this command to set or read the RS 485 M amp C remote control port configuration Syntax RC lt baud gt lt parity gt lt data_bits gt lt stop_bits gt RC Parameters Valid lt parameters gt are as follows a lt baud gt 1200 2400 4800 9600 a lt parity gt O E N odd even none a lt data_bits gt Tors a lt stop_bits gt lor 2 a Defaults 2400 0 7 1 4 20 Remote Monitor and Control Operation RD RE Receive Channel Rate Use this command to set or read the receive channel rate operation for the decoder The Receive Channel Rate should be the same as the Transmit Channel Rate TD Syntax RD lt parameter gt RD Parameters Valid lt parameters gt are a 56000 a 64000 96000 a 112000 128000 default a 192000 a 256000 a 384000 Resets the Unit Use this command to reset all of the hardware on the DAC700 Syntax RE Parameters The following volatile parameters are set a ATO a CO XXXXXXXX a CFO LB2 Additional Information Issuing an RE command is the same as power cycling the unit All volatile parameters will be reset to the their default state All nonvolatile parameters
23. operation by using an optional cable The DAC700 encoder multiplexes ancillary data along with the digitized audio Ancillary data comprises the following types of data which provide users with a number of capabilities a User data provides the capability to download pricing information music play lists or E mail files in a one to all network distribution a Relay control data offers precise uplink control of remote receivers and radio studio equipment such as cart machines a Network control command provides uplink control of some or all downlink receiver sites for channel or format changes For more information on the types of ancillary data refer to the chapter on installation and initial startup The DAC700 decoder section can be configured to accept data from the onboard encoder or from an external ISO MPEG Layer IIIA encoder that is another DAC700 When set up to receive data from the onboard encoder the decoder section of the DAC700 allows the user to monitor the audio and data that is being transmitted to the remote sites The relay control interface supports both 16 Transistor Transistor Logic TTL opto isolated sensor inputs and eight decoder output relay contacts The 16 TTL sensor inputs go to the unit controller for formatting into the system relay control messages The eight separate form A SPST relay contacts are used by the onboard decoder to control external audio or other station equipment
24. or unbalanced output drives down to 50 ohm loads no adjustments AES EBU transformer coupled balanced I O lt 0 2 at 1 kHz at 8 dBm gt 90 dB gt 90 dB at 1 kHz referenced to 18 dBu lt 67 dBm unweighted gt 85 dB referenced to 18 dBu lt 1 0 all frequencies 0 5 dB at 1 kHz no adjustments 0 5 dB 15 to 20 kHz referenced to gain at 1 kHz no adjustments gt 98 dB referenced to 18 dBu Technical Specifications and Port Information A 1 Available Audio Rates Table A 1 lists the available audio rates and bandwidths and Bandwidths Table A 1 Available Audio Rates and Bandwidths Rate kbps Audio Mode a ala Re ES DES UE d a kHz 56 Mono 8 5 6 7 Dual Mono Stereo 5 2 3 4 Joint Stereo 5 2 4 5 64 Mono 8 5 6 7 Dual Mono Stereo 4 2 3 4 Joint Stereo 5 3 4 5 96 Mono 20 10 12 14 Dual Mono Stereo 10 6 7 8 Joint Stereo 11 7 8 8 112 Mono 20 10 12 14 Dual Mono Stereo 10 6 7 8 Joint Stereo 20 10 12 14 128 Mono 20 10 12 14 Dual Mono Stereo 10 6 7 8 Joint Stereo 20 10 12 14 192 Mono 20 10 12 14 Dual Mono Stereo 20 10 12 14 Joint Stereo 20 10 12 14 256 Mono 20 10 12 14 Dual Mono Stereo 20 10 12 14 Joint Stereo 20 10 12 14 384 Mono 20 10 12 14 Dual Mono Stereo 20 10 12 14 Joint Stereo 20 10 12 14 A 2 Technical Specifications and Port Information Diagnostics Rear Panel Ports Analog Input Port Analog Output Port AUX AES Port The following diagnostics are all sele
25. selects the time interval applied to all inputs before a relay message is generated Valid values are 20 to 1 000 ms The default is 65535 65535 20 Remote Monitor and Control Operation 4 27 The IN command resets the nonvolatile parameters to their factory default settings as shown in Table 4 3 Table 4 3 Factory Default Settings Command Default Value AB 0 AG 38400 N 8 2 AM 255 AS 0 AT 0 BL 30 CF 0 Cl 1 CM 1 2 3 4 5 6 7 8 CO XXXXXXXX CS 0 0 0 0 0 0 0 0 DD 38400 N 8 1 DM 1 LB 2 LR 0 MU 0 NI 1 PC 1200 0 7 1 PD 1 1 1 1 0 38400 128000 128000 PM 0 PP 2400 0 7 1 PS 1 PT 0 RA 31 RC 2400 0 7 1 RD 128000 RM 1 TD 128000 TE 1 TM 0 TT 0 4 28 Remote Monitor and Control Operation Table 4 3 Factory Default Settings continued Command Default Value UA 1 UB 500 UC 2400 0 7 1 UT 0 XM 65535 65535 20 Remote Monitor and Control Operation 4 29 COMSTREAM A Spar Company 4 30 Remote Monitor and Control Operation Overview ComStream Packet Protocol This chapter presents an overview of the ComStream Packet Protocol and includes a Packet format and contents a Extended addressing a Controller to modem command structure and slave responses a Packet communication modes a Special packet control commands In addition specifications for the ComStream packet protocol and the physical interface connectors are described Packet Protocol Interface The ComStream packe
26. test tone is generated continuously until the operator stops it by entering the appropriate AT command parameter NOTE The audio test tone is generated internally in the decoder DSP and is therefore only testing the decoder section of the DAC700 Use the remote control computer or an oscilloscope connected to the analog output port to track the output level of the test tone The test tone frequency level should be within 0 5 dB of the stable level active balanced output drives down to 50 ohm loads or unbalanced output If the audio test tone is muted or not present check to see if the MU audio mute command is active Also check to see if the right and left channels can be reversed Check this by using the LR left right channel toggle command The CO command controls the relay contacts logically so they can be temporarily activated deactivated without physical contact closure Use this command to check for correct contact configuration and operation This command lists the current unit operating parameters Make sure the configuration parameters match the operating requirements If appropriate change the parameters to provide the intended unit performance This command resets the nonvolatile parameters to their factory default settings For a table of factory defauls see the chapter on remote monitor and control operation The RE command resets and reinitializes the unit but does not reset the nonvolatile parameters
27. 00 F116 04 Figure B 1 DB 9 Male Connector The pinout specifications for the analog output port connector are given in Table B 1 Table B 1 DB 9 Male Connector Pinouts Pin 1 0 Name Description 1 O LO Left Audio Output 2 O LO Left Audio Output 3 Not Used 4 O RO Right Audio Output 5 O RO Right Audio Output 6 O AGND Analog Ground 7 Not Used 8 Not Used 9 O AGND Analog Ground Interface Pinouts B 1 Analog Input Port J2 The pin positions for the analog input port connector are given in Figure B 2 OOO OO OOOO Figure B 2 DB 9 Female Connector The pinout specifications for the analog input port connector are given in Table B 2 Table B 2 DB 9 Female Connector Pinouts Pin 1 0 O O o oo NoN A OMN O O O Name Ll LI RI RI AGND AGND Description Left Audio Input Left Audio Input Not Used Right Audio Input Right Audio Input Analog Ground Not Used Not Used Analog Ground B 2 Interface Pinouts AUX AES Port J3 The pin positions for the AUX AES port connector are given in Figure B 3 OOOOOOOO OOOO F088 Figure B 3 DB 15 Female Connector The pinout specifications for the AUX AES port connector are given in Table B 3 Table B 3 DB 15 Female Connector Pinouts Pin 1 0 Names Description 1 O SG Signal Ground 2 O Status Status Closure Contact 1 3 PSO Preset Select Bit 0 4
28. 16 Bit Linear PCM ABR AC ADC AES EBU Amplify Analog to Digital Ancillary Data ANMS APL ASCII Asymmetric AUX bps BPSK Buffered Glossary An audio encoding format in which 16 bits of data for each sample are used with Pulse Code Modulation PCM Amps Audio Broadcast Receiver Alternating Current Analog to Digital Converter Acronym for Audio Engineering Society European Broadcast Union and their standard for digital audio interfaces To strengthen audio signals that have become weaker during processing A device that converts an analog signal to a digital signal Ancillary data is nonaudio data that is processed by the DAC700 Ancillary data has three components relay blocks network control message blocks and user data blocks For more detail see the definitions for each of the components Audio Network Management System ComStream proprietary Average Program Level American Standard Code for Information Interchange A compression technique that requires intensive processing on the compression end but little processing on the decompression end Auxiliary Bits per second Bi Phase Shift Keying Placed in a temporary storage location before being sent or received Glossary 1 CCA CD Codec Multiplexer CRC CSA DAC dB dBm dBr dBu DSP Duplex Mode EIA EMI EPROM External Baseband Input Operation LB 0 FCC Circuit Card Assembly Compact Disc A piece of equipment th
29. D be reprogrammed from its default value of 1 Please note that the RF channel configuration at the uplink must match the downlink receiver s configuration or the receiver will not acquire and output the signal For example if a channel ID other than 1 is used say 16 then ensure that the downlink ABR receivers have a channel configuration 16 defined for the proper RF receiver frequency symbol rate and demodulation type that is CC 16 11700000 128000 1 If CC 0 CC 1 or any other channel configuration number other than CC 16 is programmed into the receivers they will not acquire the channel For multiple carriers from a single uplink a good practice is to keep the network ID the same for all multiplexes The channel IDs should be consecutively ordered 1 2 3 and so on to correspond to the channel configuration numbers that are programmed into the downlink ABR units CC 1 CC 2 CC 3 and so on Table 2 1 provides an example of these different configurations and their RF channel spacing one carrier is incorrect Assume QPSK operation and 128 kbps transmission rate Table 2 1 Channel Identifier and Frequency Allocation Combinations Carrier Uplink RF Freq NI cl CC FC Format No Site MHz ABRs A X 11700 0 2 1 CC1 FD 1 2 1 7 B Y 11700 2 1 1 CC1 FD 1 1 1 7 C Z 11700 8 1 1 CC1 FD 1 1 1 7 D Z 11701 0 1 2 CC2 FD 2 1 2 7 FD 3 1 2 5 E Z 11701 2 1 3 CC2 FD 4 1 3 7 With this configuration of carrier
30. DAC700 Digital Audio Codec Multiplexer Subsystem Installation and Operation Guide Notice This publication and its contents are proprietary to ComStream Corporation ComStream and are intended solely for the contractual use of its customers for no other purpose than to install and operate the equipment described herein This publication and its contents shall not be used or distributed for any other purpose and or otherwise communicated disclosed or reproduced in any way whatsoever without the prior written consent of ComStream For the proper installation and operation of this equipment and or all parts thereof the instructions in this guide must be strictly and explicitly followed by experienced personnel All of the contents of this guide must be fully read and understood prior to installing or operating any of the equipment or parts thereof FAILURE TO COMPLETELY READ AND FULLY UNDERSTAND AND FOLLOW ALL OF THE CONTENTS OF THIS GUIDE PRIOR TO INSTALLING AND OR OPERATING THIS EQUIPMENT OR PARTS THEREOF MAY RESULT IN DAMAGE TO THE EQUIPMENT OR PARTS THEREOF AND TO ANY PERSONS INSTALLING AND OR OPERATING THE SAME ComStream does not assume any liability arising out of the application or use of any products component parts circuits software or firmware described herein ComStream further does not convey any license under its patent trademark copyright or common law rights nor the similar rights of others ComStream furthe
31. DAC700 ComStream CM701 satellite modem Radio Frequency RF terminal Antenna The DAC700 can be set up in an audio broadcast system in many ways Two of the most common ways are As an unprotected or protected encoder decoder configuration in which the DAC700 transmits compressed International Standards Organization Motion Picture Experts Group ISO MPEG Layer IIIA audio data and cue controls This data is then broadcast to and can be received by the ComStream family of audio receivers such as the ABR200 75 In a full duplex codec configuration the DAC700 can operate point to point with a DAC700 a CM701 modem and an RF terminal at each end of the link In this configuration audio data and control data can be transmitted in both directions simultaneously Asymmetric transmit and receive rates are supported This chapter provides an overview of a typical satellite digital audio distribution network as well as an overview of the DAC700 Overview 1 1 Satellite Digital Audio A satellite broadcast network consists of the following three major subsystems Distribution Network shown in Figure 1 1 OVERVIEW Satellite transmission uplink station a Satellite link a One or more remote satellite receivers Receive Site 1 Single Uplink ABR200 75 Audio Out Le gt gt Earth N Receive Only Async Data Analog Audio DAC700 CM701 Station f Antenna I AE
32. Derived timing Modem Ext timing F115 04 Figure 2 17 AES EBU Timing Input If the AES EBU stream is not present the DAC700 indicates a fault and stops sending a clock to the modem Protected mode While in LB 2 the protected mode of the DAC700 controls the terminal transmit timing clock TTCLK This is based on the frame synchronization status of the audio digital decoder within the DAC700 If the decoder is synchronized then the TTCLK is output at its prescribed rate If the audio digital decoder loses synchronization then the TTCLK is held low until it is restored A delay of up to several seconds is provided to prevent race conditions with external transmission equipment The unit controller enables the TTCLK and determines the delay value The TE Set Protected Mode command enables or disables this feature Functional Description and Theory of Operation 2 19 Sources for Decoder Input Power Module An autoswitching universal input voltage power supply provides all internal DC voltages in the unit There are two possible sources of input to the onboard ISO MPEG Layer IIIA decoder The Audio Sync indicator shows when the decoder has ISO MPEG Layer II IIA frame synchronization but does not show the source of the signal There are three defined loopback modes LB 0 LB 1 and LB 2 that are set or read using the LB command Following is a description of each loopback mode For more information on the LB command ref
33. Description and Theory of Operation On the transmit side the passthrough data is input to the unit controller encoder processor as shown in Figure 2 10 The controller transfers the formatted data to the data multiplexer DSP 3 The passthrough and ancillary data are multiplexed with the digital audio into a composite stream The composite data is then output via the broadcast data port and transmitted over the satellite in remote loopback mode l Encoder Processor Broadcast Passthrough RS 422 Data erie Data Port Sync Data In 2 J4 Including Unit Controller User Data Digitized Audio Transmit Side Digitized Audio de Broadcast Audio Dat Decoder Passthrough Sync Data roadcas udio Data assthroug including Data Port Decoder Processor t j Data User Data J4 DSP 4 Out 2 Unit Controller Receive Side a Figure 2 10 Data Passthrough Processing The DAC700 transmits all blocks successfully received based on ComStream proprietary protocol definition Blocks not successfully received are discarded On the receive side the loopback composite data is demultiplexed by the audio data decoder DSP 4 into separate digital audio and ancillary data streams The ancillary data is transferred to the unit controller where it is demultiplexed and output via channel 2 of the data port Only passthrough data will be accepted through channel 2 Implementation Two dual channel Universal Asynchr
34. Functional Description and Theory of Operation 2 1 The DAC700 unit can connect via the Monitor amp Control M amp C port in either RS 232 or RS 485 format to an external portable terminal desktop computer or terminal emulator The computer can be used to issue control configuration and diagnostics commands By means of the DAC700 s extensive query command capability the computer can also be used to monitor unit codec mux operating status and fault and alarm information The clock module produces all the clocks and event timing necessary for the unit Two separate clock generator circuits are available to support independent asynchronous transmit and receive operations This chapter presents a description of the following DAC700 chassis DAC700 front panel indicators ISO MPEG Layer II IA Transmission channel signal format DAC700 major functional modules DAC700 loopback modes DAC700 Chassis The DAC700 consists of a single Circuit Card Assembly CCA enclosed in a chassis The chassis consists of a standard 19 inch wide enclosure one rack unit high The front view of the DAC700 is shown in Figure 2 1 Digital Audio Codec Mux DAC700 Power Audio Sync DualMono Joint Stereo Overload Fault F093 Figure 2 1 DAC700 Front Panel For ease of installation all input and output connections are made on the rear panel shown in Figure 2 2 analog OUTPUT MEA INPUT ac BROADCAST DATA sch DATA RELA
35. IIA Commentary 64 kbps mono Layer II The classification of 192 kbps for the emission grade is based on recent work at the Institute fur Rundfunk Technique IRT and relies on the intensity joint stereo coding technique for additional compression Tolerance to transmission errors The ISO MPEG Layer IIIA data block consists of two parts The first is the header and consists of framing bit allocation scale factors and other side information The second part of the frame is the audio data In the case of 256 kbps per stereo channel the length of a 24 ms frame is 6 144 bits the header part of the frame is approximately 300 bits and the remainder of the frame is the audio data The bit integrity of the entire header is vital since it defines the layout of the remainder of the frame Any bit error in the header causes degradation because the following parts of the frame would be decoded incorrectly and thus 24 ms of audio would be lost 2 1 4 ISO MPEG Layer II IIA Functional Description An error in the data part of the frame can range from imperceptible to just barely noticeable This is due to the fact that a single bit error only affects a single data sample thus only a very small time If the bit error occurs in the least significant bit of the data sample the effect of the error is minimal However if the error occurs in the most significant bit the sign bit then the effect is more pronounced The header of a
36. PEG A B ADC DSP 2 Data Ancillary Data Analog Analog Audio AES FBU Aux AES AES EBU Audio Cem eal pean igital Port J3 Interface AES EBU yne J4 Audio In NUK oF 2 J4 once Ancillary Data Digital Fo72 Figure 2 7 Audio Input Interfaces Functional Description and Theory of Operation 2 9 Audio Output Interfaces Transmitted data is received via the broadcast data port as shown in Figure 2 8 The audio data decoder DSP 4 separates the data into ISO MPEG Layer II IIA digital audio and ancillary data streams The audio data stream goes to the Digital to Analog Converter DAC Digital to Analog Analog Converter Audio Out DAC Channel A B Analog Broadcast Audio Data Data Port Decoder J4 DSP 4 RS 422 Sync ISO MPEG Data AES EBU Digital it Audio Out AES EBU Aux AES Interface Port J3 Digital F073 Figure 2 8 Audio Output Interfaces The DAC is a dual channel oversampling device operating at a 48 kHz sample rate It converts the digital audio into analog audio that is transferred via the analog output port to the external sound equipment Digitized audio may also be output The audio data decoder converts the signal to 16 bit linear PCM data and sends it to the AES EBU interface The resulting AES EBU audio data in serial form is output via the AUX AES port Both the analog audio and the AES EBU digital format are output at the same time The appropriate transmit and recei
37. Right Channel Toggle Use this command to set or read the sense of the left and right audio channel output on the DAC700 decoder only Syntax LR lt parameter gt LR Parameters Valid lt parameters gt are a 0 Normal sense default a Reverse sense a 2 Left input on both left and right output a 3 Right input on both left and right output This will not affect the sense of the audio transmitted to the receiver Audio Mute Use this command to set or read the muting of both the analog and digital audio outputs of the DAC700 decoder Syntax MU lt parameter gt MU Parameters Valid lt parameters gt are a 0 Unmuted audio outputs enabled default a 1 Muted audio output disabled a 2 Left channel muted right channel unmuted a 3 Right channel muted left channel unmuted This will not affect the audio transmitted to the receiver Remote Monitor and Control Operation 4 15 NI PC Network ID Use this command to set or read the network ID number that is sent out as part of the relay control message Syntax NI lt parameter gt NI Parameters Valid lt parameter gt range is 1 through 255 The default is 1 RS 232 Monitor and Control Port Configuration Use this command to set or read the RS 232 M amp C port configuration Syntax PC lt baud gt lt parity gt lt data_bits gt lt stop_bits gt PC Parameters Valid lt parameters gt are as fol
38. S EBU gt Telco R elay Contacts Data gt r y Control gt Optional Channel Control Relays gt External Alarms e e e Receive Site N ABR200 75 1 Audio Data Relays gt aBR200 75 2 Receive Only Audio Data Relays gt Antenna 4 ABR200 75 3 Audio Data Relays gt F092 Figure 1 1 Single Channel to Multipoint Audio Data Satellite Network The hub or satellite transmission uplink station is the facility where the audio to be transmitted is collected and uplinked to the satellite This facility consists of the following a Audio encoder multiplexer such as the DAC700 a Digital modem such as the CM701 a Farth station such as the DT7000 a Antenna such as those provided by Prodelin a Optional audio network management system ANMS a Optional terrestrial link to provide dial up diagnostics and performance monitoring The satellite link consists of a commercial telecommunications satellite in geosynchronous orbit above the earth Two RF bands that are primarily used are C band and Ku band 1 2 Overview The third major subsystem the remote satellite receiver includes a Satellite antenna subsystem a Interfacility link IFL cable a Satellite audio receiver A number of configurations are possible depending on the size of the network Networks are often a single channel uplink to multipoint downlinks On the uplink side a DAC700 unit connects to a ComStream CM701 modem
39. Table 6 2 Table 6 3 Table A 1 Table A 2 Table A 3 Table B 1 Table B 2 Table B 3 Table B 4 Table B 5 Table B 6 Table B 7 Channel Identifier and Frequency Allocation Combinations 2 6 Timing Source 2 17 Quality Grades and Bit Rates 2 1 4 Bit Rate and Encode Decode Cycles 2 1 6 Installation Sequence 3 1 Error Codes and Descriptions 4 2 DAC700 Command Summary 4 2 Factory Default Settings 4 28 Packet Protocol EM Query Command 5 6 RS 485 Device Pinout Specifications 5 7 Key Performance Montoring and Maintenance Commands 6 2 Fault Conditions 6 4 DAC700 Unit Troubleshooting 6 7 Available Audio Rates and Bandwidths A 2 Rear Panel Port Mapping A 3 LED Descriptions A 5 DB 9 Male Connector Pinouts B 1 DB 9 Female Connector Pinouts B 2 DB 15 Female Connector Pinouts B 3 DB 15 Female RS 422 Connector Pinouts B 4 DB 9 Female RS 232 Connector Pinouts B 5 DB 9 Female RS 232 or RS 485 Connector Pinouts B 6 DB 37 Female Connector Pinouts B 7 viii Contents Using this Guide Conventions Used in this Guide Preface Welcome to the ComStream world of satellite based communication systems and networks This guide is your sourcebook for using the ComStream DAC700 Codec Multiplexer It describes the installation operation and performance specifications of this product The chapters in this guide provide step by step instructions for a variety of tasks and activities including unpacking setting up mounting and oper
40. Y CONTROL Se of SES Jo Ck of Jo Ce of Jo O Figure 2 2 DAC700 Rear Panel Functional Description and Theory of Operation Front Panel Indicators The front panel of the DAC700 has six indicators located on the right side of the panel as shown in Figure 2 3 The indicators are backlit to show active operation status or faults in the DAC700 unit Digital Audio Codec Mux DAC700 Power Audio Sync Dual Mono Joint Stereo Overload Fault F095 Figure 2 3 DAC700 Front Panel Indicators The green Power LED indicates the unit is powered on and the power supply is functioning correctly The Audio Sync illuminates green to indicate the decoder has ISO MPEG Layer MIIA music frame synchronization The Dual Mono is a green LED that indicates the current mode of operation a On indicates the audio digital encoder is performing independent stereo coding in dual mono mode a Off indicates the unit is operating in mono mode or joint stereo mode Refer to the following description of Joint Stereo mode The Joint Stereo is a green LED a On indicates the audio digital encoder is in joint stereo coding mode a Off indicates the unit is operating in mono mode or in the dual mono operating mode Refer to the previous description of the Dual Mono mode When both the Dual Mono and Joint Stereo indicators are off the unit is in mono operation The Overload LED illuminates red to indicate that o
41. 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 Warning Shock Hazard Do Not Open The Equipment Service Only By ComStream Gef hrliche Spannung ffnen des Ger tes und Service nur durch ComStream The DAC700 Codec Multiplexer contains no user serviceable parts Do not attempt to service this product yourself Any attempt to do so will negate any and all warranties This symbol is intended to alert the user to the presence of important operating and maintenance servicing instructions in the literature accompanying the appliance Preface Chapter 1 Chapter 2 Contents Using this Guide ix Conventions Used in this Guide ix Warranty Statement xi Return Procedure xii Revision History xiii Customer Support xiii Safety Precautions xiv Overview Introduction 1 1 Satellite Digital Audio Distribution Network Overview 1 2 DAC700 Features 1 4 Functional Description and Theory of Operation Overview 2 1 DAC700 Chassis 2 2 Front Panel Indicators 2 3 Transmission Channel Signal Format 2 4 Proper Signal Discrimination of Narrow Band RF Signals 2 5 DAC700 Major Functional Modules 2 7 Audio Input Interfaces 2 9 Audio Output Interfaces 2 10 Broadcast Data Interface 2 10 Data Interfaces 2 11 Monitor and Control Interface 2 14 Relay Control Interface 2 14 Audio Data Encoder 2 15 Data Multiplexer 2 16 Audio Dat
42. a Decoder 2 16 Unit Controller 2 16 Clock Generator 2 17 Power Module 2 20 Sources for Decoder Input 2 20 LB 0 External Baseband Input Operation 2 20 LB 1 PCM Loopback Operation 2 21 LB 2 Normal Operation 2 22 Contents iii Chapter 2 1 Chapter 3 Chapter 4 ISO MPEG Layer II IIA Functional Description Overview 2 1 1 Compression Concepts 2 1 1 Performance Considerations 2 1 3 Installation and Initial Startup Overview 3 1 Site Planning and Preparation 3 1 Location Requirements 3 2 Mounting the DAC700 3 2 External Connections 3 2 Analog Output 3 3 Analog Input 3 3 AUX AES 3 3 Broadcast Data 3 4 User Data 3 4 M amp C 3 4 Relay Control 3 5 Initial Power Up 3 5 Installation Check 3 5 Firmware Version 3 7 Initial Configuration 3 7 Audio Bandwidth Configuration 3 7 User Data Configuration 3 8 Passthrough Mode Configuration 3 9 Encoder Decoder Ancillary Data Rate Configuration 3 9 User Relay Configuration 3 10 Network and Channel Definitions 3 11 Timing Source Configuration 3 11 Remote Monitor and Control Operation Overview 4 1 Command Syntax 4 1 Command Error Codes 4 2 Command Summary 4 2 Detailed Command Descriptions 4 4 iv Contents Chapter5 ComStream Packet Protocol Overview 5 1 Packet Protocol Interface 5 1 Packet Protocol Messaging 5 1 Packet Format and Content 5 2 ComStream Packet Protocol Address Selection 5 3 Extended Addressing 5 4 Packet Protocol Command Structure 5 4 Status Que
43. all outlet and disconnecting the coaxial cable Preface XV Turn Modem Off When Changing Circuit Boards Turn modem off before installing or removing any circuit boards from chassis slots Possible damage may occur to modem boards or related equipment if power is left on during this procedure Provide Antistatic Protection Wear a properly grounded antistatic wrist strap to prevent electrostatic damage to components when handling circuit boards or other electronic modules Keep Objects Outside Touching internal DAC700 Codec Multiplexer parts is dangerous to both you and the unit Never put any object including your fingers through DAC700 Codec Multiplexer slots or openings as this could result in touching dangerous voltage points short circuiting parts electric shock or fire There are no user serviceable parts inside the DAC700 Codec Multiplexer If an object falls into the DAC700 Codec Multiplexer unplug the unit and contact ComStream Customer Service as serious damage could occur to the DAC700 Codec Multiplexer or its components Use Approved Attachments Only Use only ComStream approved option cards and other satellite communication equipment with the DAC700 Codec Multiplexer Clean the DAC700 Codec Multiplexer Before cleaning the DAC700 Codec Multiplexer unplug it from the wall outlet Do not use water or any type of abrasive pads scouring powders liquid cleaners aerosol cleaners or solvents such as alcohol or
44. an output channel from the decoder Both the input and output channels are serial digital with balanced line transformer coupled interfaces The AUX AES port also provides three preset inputs that can be programmed to automatically switch the DAC700 to operate in any of eight predetermined formats In addition two status closure contacts provide codec alarm relay fault status and the remote control reset initializes the M amp C port in the default configuration Installation and Initial Startup 3 3 Broadcast Data The broadcast data port provides the composite audio and multiplexed data to and from the satellite modem It is a full duplex synchronous RS 422 interface The transmit and receive channels operate independently at data rates from 56 to 384 kbps Transmit timing for data output may be derived from four sources Receive timing for data input may be derived from two sources For timing definitions refer to the chapter on functional description and theory of operation User Data The user data port consists of two separate asynchronous RS 232 serial ports Each serial channel operates independently Rates can be selected via the M amp C port Data 1 channel provides transmit direction hardware flow control and operates at rates from 300 to 9600 bps Data 2 channel is used as an input output path for the data passthrough mode and operates at rates from 300 to 9600 bps M amp C The M amp C port can be used to connect t
45. and RF terminal On the downlink side there are a number of ComStream ABR receivers and RF terminals This configuration is shown in Figure 1 1 For larger networks a multichannel uplink to multipoint downlink architecture is used as shown in Figure 1 2 On the uplink side two or more DAC700 units connect to CM701 modems and RF terminals On the downlink side there are multiple ABR receivers In this configuration the audio network management control system ANMS is recommended The ANMS communicates with the entire network of audio satellite receivers via the audio codec mux unit and provides the system control from the uplink Uplink p Receive Site 1 Transmit os ABR200 75 Audio Out __ gt i S Receive Only I Async Data Antenna I V2 Relay Contacts Modem Optional Channel Control External Alarms User Data e ISa e EU Uplink e E i MC Receive Site N Audio Network Source s Control aona ABR200 75 1 Audio Data Relays aE gt Relay Control DIRE Telco ABR200 75 2 Audio Data Relays io Network modem 7 eS E gt Audio Network Antenna Management System TAS Optional ABR200 75 3 Audio Deta Raley Ss gt F091 Figure 1 2 Multichannel to Multipoint Audio Data Satellite Network Overview 1 3 DAC700 Features The DAC700 is a multirate audio encoder decoder The DAC700 shown in Figure 1 3
46. ansmission and the block is terminated A zero value character disables input termination Example If N 65 when ASCII A is detected in the input user data stream the current user data block is sent out with A as the last character If N 65 when A is detected the block is sent without A 4 26 Remote Monitor and Control Operation XM Relay Mapping Use this command to set or read the relay input port configuration Syntax XM lt active_input_mask gt lt polarity_mask gt lt debounce gt XM Parameters The three lt parameters gt are defined as follows lt active input mask gt The active input mask selects which of the 16 inputs will be used in forming the relay control word The mask is specified in a decimal format with 65535 selecting all 16 bits zero selects no active inputs Selection numbers other than zero are Sensor Input Number Selection Number 0 1 1 2 2 4 3 8 4 16 5 32 6 64 7 128 8 256 9 512 10 1024 11 2048 12 4096 13 8192 14 16384 15 32768 lt polarity mask gt The polarity mask selects the sense of the input on a bit basis in decimal format A 1 selects inverted and a 0 selects no inversion For example 65535 selects all bits to be inverted before being transmitted Zero selects all bits to be noninverted Given active low hardware inputs the inverted state 65535 provides true polarity in the relay message packet lt debounce gt The debounce
47. at combines the functions of both a codec and a multiplexer codec consists of a series of integrated circuits that perform a specific analog to digital conversion The DAC700 codec converts analog sound signals to a digital bit stream A multiplexer simultaneously transmits two or more messages on a single transmission path The multiplexer also receives messages and controls the communication lines Cyclic Redundancy Check Canadian Standards Association Digital to Analog Converter Decibels Decibels referenced to 1 milliwatt Decibels above reference number Decibels relative to a reference of 0 775 volts RMS Digital Signal Processor A specialized digital microprocessor that performs calculations on the digitized signals that have been converted from analog and sends the results on An optional configuration for operating the DAC700 In duplex mode the DAC700 encodes and sends the digitally compressed data out and loops it back through its onboard decoder The signal is then available as needed for monitoring performance Electronic Industries Association Electromagnetic Interference Erasable Programmable Read Only Memory In external baseband input operation an ISO MPEG Layer IIIA stream from an external source is brought in through the broadcast data port decoded and then sent out the audio output ports An independent ISO MPEG Layer IIIA stream can also be sent out the broadcast data port Federal Communications Commiss
48. at would obstruct the required airflow into the DAC700 Codec Multiplexer ventilation slots Use Correct Power Source The DAC700 Codec Multiplexer comes equipped with both a North American and Internationally compatible power cord The North American power cord has an IEC compatible female plug on one end and a North American compatible male plug on the other This cord is UL and CSA approved up to 125 VAC at 10A This cord is ready to use with no user wiring required The International power cord has an IEC compatible female plug on one end and three stripped and tinned bare wires on the other end This cord is approved by many international safety agencies including VDE up to 250 VAC at 6A This cord wire complies with the international color codes of ground is green yellow neutral is blue and line is brown If these color codes do not correspond to the colored markings on the terminals in the plug use the following standards The green yellow wire must be connected to the plug terminal marked by the letter E or by the earth symbol or colored coded green and yellow The blue wire must be connected to the plug terminal marked with the letter N or colored coded black The brown wire must be connected to the plug terminal marked with the letter L or colored coded red xiv Preface An AC plug must be attached to the international power cord in accordance with government standards and codes in effect at the DAC700 Codec Multiple
49. ating the DAC700 Codec Multiplexer The chapters also provide an overview of system operations as well as technical specifications and troubleshooting procedures This guide is designed to help you find and use information quickly and easily To take full advantage of this design please take a moment to review the specific formats Locating Information There are several tools located in this guide to help you quickly locate information The table of contents located at the beginning provides you with an outline of the chapters and major topics contained within them A detailed description of each chapter is contained in the next section titled Organization The glossary and index are located at the end of this guide The glossary contains technical terms and system commands for easy reference The Index can be used to help you quickly locate information Important Information Throughout this guide you will find three icons designed to help you identify important information These symbols are The note icon identifies information for the proper operation of your equipment including helpful hints shortcuts or important reminders The caution icon identifies information that requires careful attention in order to prevent equipment damage and or injury to the operator The troubleshooting icon identifies information that will assist you in solving malfunctions in your equipment Illustrations Some illustrations contained in t
50. benzene Use only a clean soft cloth lightly moistened with a mild detergent solution Wipe all equipment with a clean soft cloth lightly moistened with water to remove the detergent solution Service the DAC700 Codec Multiplexer Do not attempt to service the DAC700 Codec Multiplexer yourself as there are no user serviceable parts Opening or removing covers may expose you to dangerous voltages or other hazards as well as void your warranty Contact ComStream Customer Service to obtain qualified service personnel The following conditions indicate that the DAC700 Codec Multiplexer needs servicing a The power cord or plug has been damaged An object has fallen into the receiver Liquid has been spilled into the DAC700 Codec Multiplexer or it has been exposed to rain or water a The unit has been dropped or the cover has been damaged a The DAC700 Codec Multiplexer does not operate normally or shows a marked change in performance Perform Safety Checks Upon completion of any service or repairs to the DAC700 Codec Multiplexer or its option cards ask the service technician to perform safety checks to verify that the system is in safe operating condition xvi Preface Introduction Overview The DAC700 audio codec multiplexer subsystem is a key component of the ComStream digital audio broadcast system The following equipment is all that is needed to provide a complete CD quality digital audio satellite uplink
51. bled default The decoder input comes from the encoder s output and the transmit terminal timing output is qualified with the decoder s audio frame sync status Remote Monitor and Control Operation 4 23 TT Encoder Transmitter Mode Use this command to set or read the encoder mode Syntax IM lt parameter gt TM Parameters Valid lt parameters gt are as follows a 0 Mono default a 1 Dual mono a 2 Joint stereo Transmit Timing Selection Use this command to set or read the transmit timing mode Syntax TT lt timing mode gt LE S Parameters Valid lt timing mode gt values specify the mode as follows a 0 Internal default a 1 External from ST input a 2 External from RT input a 3 AES EBU Interface 4 24 Remote Monitor and Control Operation UA UB Relay Data In Band Signaling Use this command to turn on and off decoder relay data and or IBS The command does not effect encoder relay data or IBS Syntax UA lt parameter gt UA Parameters Valid lt parameters gt are Relay Data IBS Off Off Off On Off Off On On Off On On On C I WF O Additional Information Seven 7 indicates that all switches relay data and IBS are ON it is the default User Data Time or Send Interval Use this command to allow the user to determine the period at which user data is sent out with the aggregate data Syntax
52. ce 2 16 description 3 3 interface pinout B 1 port number A 3 Ancillary data audio input interfaces 2 9 data channel 1 2 11 receive side 2 12 decoder processing 2 16 Ancillary data configuration bandwidth definition 3 9 bandwidth guidelines 3 9 network control messages 3 9 relay blocks 3 9 setting the data rate 3 10 setting the mux demux mode 3 10 user data blocks 3 9 Audio bandwidth configuration setting the bandwidth 3 8 setting the receive rate 3 8 setting the transmit mode 3 8 setting the transmit rate 3 8 Audio input analog audio 2 9 digitized audio 2 9 interfaces 2 9 transmit and receive timing signals 2 10 Audio output interfaces 2 10 Audio performance analog input levels A 1 analog sampling rate A 1 channel mute A 1 compression technique A 1 crosstalk A 1 digital I O A 1 dynamic range A 1 end end gain stability A 1 frequency response A 1 idle channel noise A 1 input impedance A 1 operating modes A 1 operation A 1 output levels A 1 signal to noise A 1 stereo phase deviation A 1 total harmonic distortion A 1 Audio data decoder audio output interfaces 2 10 description 2 16 Audio data encoder audio input interfaces 2 9 description 2 15 AUX AES port number A 3 AUX AES port A 3 audio input interfaces 2 9 description 3 3 interface pinout B 3 Available audio rates and bandwidths A 2 B Broadcast data port A 4 audio input interfaces 2 9 audio output interfaces 2 10 data channel 1 2
53. ce of sufficient size and strength where it will not be jarred hit or pushed off its surface Ensure that all cables and cords are out of the way and will not be tripped over as this could cause personal injury or serious damage to the DAC700 Codec Multiplexer Avoid Water and Moisture Do not expose the DAC700 Codec Multiplexer to any liquids which are often found in flower vases coffee cups rain from open windows etc If the DAC700 Codec Multiplexer is exposed to any liquid contact ComStream as serious damage could occur to the DAC700 Codec Multiplexer or its components Avoid Heat Humidity and Dust To avoid internal damage the DAC700 Codec Multiplexer should be placed away from all heat sources including radiators heater ducts etc out of direct sunlight and away from high humidity excessive dust or mechanical vibrations that can cause damage to internal parts Provide Adequate Ventilation Slots and openings on the DAC700 Codec Multiplexer are provided for ventilation that is needed to ensure reliable operation To avoid overheating and ensure that the ventilation slots are not blocked place the DAC700 Codec Multiplexer on a smooth hard surface that has at least two inches of clearance around the unit and adequate air circulation If the DAC700 Codec Multiplexer is placed in a closed area such as a bookcase or rack ensure that proper ventilation is provided Never place the DAC700 Codec Multiplexer on a soft surface th
54. ced noise remains inaudible Quantization noise can be better adapted to the masking threshold of the human ear by splitting the frequency spectrum into subbands The quantization of the analog time samples required for each individual subband is dependent on the minimum masking value in each subband This minimum masking level is a measure of the allowed quantization noise which is just below the level of perceptibility Subbands with desired signals well below the masking threshold thus irrelevant for the human ear do not need to be transmitted In each 24 ms period a calculation of the masking threshold is performed for each subband This threshold is then used to compute the best psychoacoustical allocation of the available bits This process is called dynamic bit allocation Audio data is quantized using the dynamic bit allocation thus the required bit rate for time variant audio signals changes continuously due to the changing masking threshold If there are an insufficient number of bits to completely hide the quantizing induced noise then the noise is placed in the least objectionable place in the audio sample If there is an excess number of bits then the extra bits are used to reduce the quantizing induced noise to as low a level as possible The allocation of the extra bits is crucial and allows multiple encode decode cycles as well as postproduction of the audio The total transmitted bit stream contains quantized audio values
55. cility AC line power as follows a 90 VAC to 264 VAC o 47 to 63 Hz a 40 W service with circuit breaker and integral ground protection o One or more lightning and surge protector o Cable run to AC power connector on rear of unit with 3 ft 1 m relief length ComStream recommends an uninterruptible power supply UPS a line conditioner or both where power is subject to surges unstable or noisy conditions or outages Adequate distance between the DAC700 unit and electromagnetic interference EMI sources such as AC power generating equipment Proximity of 25 ft 7 62 m or less to equipment providing specified signal I O levels for RS 422 RS 232 or optional RS 485 interfaces The DAC700 works in concert with the CM701 modem The DAC700 has been thermally designed to be placed in a 19 inch rack in a pattern of alternating DAC700s and CM701s CM701 DAC700 CM701 DAC700 etc If the DAC700 is not used with the CM701 it is recommended that one unit of rack space be left open above each DAC700 unit to ensure adequate airflow The rack must be ventilated so that the internal ambient temperature does not exceed the DAC700 s maximum ambient temperature of 50 C This section describes the physical and electrical connections to the DAC700 Ensure that all cables are installed before connecting to an AC power source Installation and Initial Startup All external connections to the DAC700 are made through the rear panel connectors
56. cond dual mono at 256 kbps using Bi Phase Shift Keying BPSK modulation Figure 2 4 illustrates various digital audio carriers that might occur on a single transponder 36 MHz Transponder Other SCPC Mono 4 ae ay oO lt Se NN mee ae o e o O O O O g g e E g p amp a a 2 2 2 Q8 HH 5 D D D 6 x T a o gt 2 e 2 2 o o O D D E 5 e 2 T T T oO a A A A Central Uplink F071 Figure 2 4 Multichannel Single Transponder System 2 4 Functional Description and Theory of Operation The TDM frame structure is provided by the ISO MPEG Layer II IIA audio standard as shown in Figure 2 5 The frame header provides all information regarding the audio rate compression mode mono dual mono stereo joint stereo sampling rate 48 kHz and ancillary data size For error detection a Cyclic Redundancy Check CRC checksum is included within the frame header 24 ms Frames IK ISO MPEG Audio Data Ancillary Data A Audio Frame Data Data Data Data Data Data B User Data Frame F100 Figure 2 5 DAC700 Channel Format The audio data is the digitally compressed data generated by the ISO MPEG Layer IIIA encoder section of the DAC700 The ancillary data stream comprises three types of control blocks a Network control a User data a Relay cue signaling As shown in Figure 2 5 the ancillary data is
57. ctable from the M amp C port PCM Loopback PCM output of A D is fed directly into D A Normal Operation Decoder input comes from encoder output instead of the broadcast data port Test Tone Output 1 000 Hz and 9 600 Hz left only right only or both channels Rear Panel Port Mapping Rear panel port mapping is shown in Table A 2 Table A 2 Rear Panel Port Mapping Port Number Port Name Ji Analog Output J2 Analog Input J3 AUX AES J4 Broadcast Data J5 User Data J6 M amp C J7 Relay Control Connector DB 9 female Connector DB 9 male Interface Type Transformer coupled balanced I O Connector DB 15 female Technical Specifications and Port Information A 3 Broadcast Data Port User Data Port Passthrough Port Relay Control Port M amp C Port Interface Type Data Rates Connector Clocking Operating Modes Interface Type Data Rates Connector Interface Type Data Rates Connector Recoder Output Contact Closures Encoder Inputs Connector Interface Type Connector Functions Asynchronous RS 422 56 64 96 112 128 192 256 and 384 kbps DB 15 female Internal external or derived from AES EBU 1 Normal 2 Protected decoder sync status controls clock presence Asynchronous RS 232 300 1200 2400 4800 and 9600 baud DB 9 female Asynchronous RS 232 300 1200 2400 4800 and 9600 baud DB 9 female 8 form A individually controlled 16 TTL opt
58. decoder processor also receives relay control data and controls the eight decoder output relay contacts 2 16 Functional Description and Theory of Operation Clock Generator The clock generator module shown in Figure 2 13 produces all the clocks and event timing necessary for the system Two separate clock generator circuits are provided to support independent asynchronous transmit and receive operations There are four selectable clock sources available to the user Clock Generator Transmit cy tt Transmit Clock Clock TxCLk Send Timing ST Receive Receive Timing RT Receive _ Clock Clock RXCLK AES EBU Timing Input F078 Figure 2 13 Clock Generator The transmit clock generator circuit can derive clocking from one of the four sources shown in Table 2 2 The TT Transmit Timing Selection command selects which timing source to use For more information on the TE command refer to the chapter on remote monitor and control operation Table 2 2 Timing Source TT Timing Source Figure 0 Internal 12 288 MHz crystal oscillator PLL 2 14 1 External from send timing ST RS 422 input from the 2 15 broadcas tdata port that is from the modem send timing 2 External from receive timing RT RS 422 input from the 2 16 broadcast data port that is from the modem receive timing 3 AES EBU digital clock input External 2 17 Functional Description and Theory of Operati
59. dress Byte ata E Checksum ETX F205 01 Figure 5 1 Packet Format Each byte within the packet is defined as follows a STX Signifies the beginning of a packet Its ASCII value is STX 02 a Byte Count Represents the total number of bytes in the packet including the STX and ETX The minimum count is 6 and the maximum count is 127 a Device Address Indicates the destination of a packet and is bit mapped as follows a Bits 0 4 signify the slave address Although each slave recognizes only those packets that are addressed to it all slaves will also respond to but not acknowledge packets addressed to device address zero a Bit 5 is always 1 a Bit 6 is the address extension bit This bit allows a packet to be addressed to a nonprimary device that is a device not directly connected to the primary RS 485 bus When set additional address fields will follow Address extension bit parameters are e 0 No address extension e 1 Address extension Refer to the Extended Addressing section in this chapter for a more detailed explanation ComStream Packet Protocol a Control Byte Provides control information to the receiving device It is bit mapped differently for controller to slave or slave to controller communication Bit maps are as follows o For controller to slave communications e Bit 0 represents the packet acknowledge request as follows OQ slave should not acknowledge receipt of packet
60. ds on the command issued by the controller The slave s response to a configuration or control command will be either a Empty packet no data field if the command was successfully completed a Error sequence if the slave was not able to execute the requested modification The slave s response to a status query will be either a Message packet containing status information consisting of the queried parameter an ASCII space and the parameter value or status information Error sequence if the slave was unable to obtain the queried parameter information 5 6 ComStream Packet Protocol Special Packet Control Commands ComStream Packet Protocol Specifications Most of the standard modem monitor and control commands are supported by ComStream packet protocol Commands which result in a response that exceeds the maximum packet byte count of 127 bytes are not supported All DAC700 commands are supported The interface signal levels and electrical characteristics are in accordance with the IA RS 485 full duplex tri state interface bus standards The bus is configured as a party line with a maximum of 32 devices connected to a single bus The physical interface connector is a 9 pin D type connector Table 5 2 lists the pinout specifications for an RS 485 device Table 5 2 RS 485 Device Pinout Specifications Pin Signal Direction 1 Rev In 5 Gnd 7 Rev In 8 Xmit Out 9 Xmit Out 2 3 4 6 No Connection
61. e of the DAC700 To use this mode three commands need to be configured Preset Definition PD Preset Mode PM and Preset Selection PS Using the PD command the user enters resets for all the channels in the system into a spare DAC700 for redundancy protection To enable the preset mode the user sets the PM command for each DAC700 to 1 When a fault is detected and the modem protection switch performs a channel switchover the address of the faulty channel is sent to the spare DAC700 and a signal routing switch With PM 1 the spare DAC700 receives the address selects the preset for that channel and uses these parameters to reconfigure itself to mirror the faulty channel Upon receiving the faulty channel s address the signal routing switch selects the faulty channel s audio input and routes it to the spare DAC700 to complete the switchover Once the switchover is complete the signal from the spare codec modem pair proceeds to the RF terminal to be transmitted to the satellite via a satellite antenna and then to the receiving sites Remote Monitor and Control Operation 4 17 PM Preset Mode Use this command to set or read the preset mode Syntax PM lt parameter gt PM Parameters Valid lt parameters gt are as follows a 0 Mode is disabled default a 1 Presets are controlled from the three hardware input lines a 2 Presets are controlled by the PS command Additional Information In mode 1 t
62. eam Customer Service at 619 657 5454 or toll free at 888 559 0831 Preface xi Return Procedure If itis necessary to return a product for out of warranty repair upgrade or any modification the following procedures must be followed 1 Contact ComStream Customer Service located in the United States via phone or fax o Phone 619 657 5454 or toll free at 888 559 0831 o Fax 619 657 5455 2 Speak to a ComStream customer service representative about any questions issues or problems Quite often equipment problems can be corrected over the phone which keeps your equipment in service and avoids unnecessary and costly downtime 3 Should it be necessary to return a product to ComStream for any reason the ComStream Customer Service representative will issue you a return material authorization RMA number To issue an RMA number the ComStream representative will need the product s serial number and model number 4 You may be returning a product for either repair upgrade or modification If you are returning the product for a Repair please include a complete serial number of the unit description of the problem the operating conditions which caused the problem and any circumstances that may have led to the problem This information is essential for ComStream repair technicians to reproduce diagnose and correct the problem a Upgrade or modification please include a complete description of the current configuration and t
63. ed Addressing The ComStream packet protocol allows hierarchical addressing Any device within the packet network may be addressed by providing a full address path The address field of a packet may be extended indefinitely if a Appropriate address extension bits are set a Maximum packet length is not exceeded Intermediate ComStream devices in the addressing chain automatically forward the packet to the next device in the chain Response packets originating from the last device in the chain are forwarded until they reach the controller If an acknowledge packet is required the controller must adjust its time out period to account for the packet forwarding delay encountered within the device hierarchy All commands are initiated by a controller that sends addressed packets to the slave units on the packet party line interface A controller command can be Configuration Control Status query All commands are issued by the controller as odd parity and 7 data bits All responses are returned as odd parity and 7 data bits with the exception of BD command responses For a listing of specific configuration control or query commands refer to the chapter on remote monitor and control operation Configuration or control commands The structure of configuration and control commands consists of a Two or three letter mnemonic ASCII string a Single ASCII space character a Optional ASCII parameter string Configuration and co
64. ed inputs that can be mapped to an audio receiver s eight output relays for control of external studio units such as a console control or event sequencer Overview a Provides eight dry contact relay outputs from the onboard decoder to external units such as a studio console control or event sequencer a Offers users the selection of four different clock sources one internal and three external a Has built in diagnostics that include local and remote loopback of audio data operating status fault alarms and output status relay a Provides front panel operating status and fault indicators The remaining portion of this guide describes in detail the steps necessary to install configure and operate the DAC700 audio codec mux within a network environment Overview 1 5 COMSTREAM A Spar Company 1 6 Overview Overview Functional Description and Theory of Operation The DAC700 accepts either analog audio or AES EBU formatted digital audio from a studio source The DAC700 can encode and decode this audio as well as ancillary data using the ISO MPEG Layer II ITA audio compression algorithm The DAC700 has three operating modes for system audio a Mono a Dual mono stereo a Joint stereo The DAC700 has the flexibility to have either 600 ohm balanced or gt 100 kohm audio input impedance The factory internally configures the DAC700 for gt 100 kohm input impedance It can also be configured to 600 ohm balanced
65. embedded into the outbound digital stream that is then sent to the modem for the uplink At the ABR receiver the ancillary data is stripped out by the ISO MPEG Layer IIIA decoder and sent to a control microprocessor for additional processing Proper Signal Discrimination of Narrow Band RF Signals The acquisition range of the ABR200 75 receivers work over a very large frequency range approximately 2 MHz With the possibility of having multiple carriers over that range a means to uniquely identify one RF carrier from another is needed to ensure the correct RF signal is received and processed as desired Discrimination is provided by the DAC700 when it embeds a unique identifier into the relay control block of the ancillary data of the ISO MPEG Layer H A compressed audio output stream This unique identifier has two components a network ID and a channel ID The programmable values for the IDs are generated by the DAC700 codec mux at regular intervals multiples of 100 ms Functional Description and Theory of Operation 2 5 For a given uplink each codec mux is programmed with a unique channel number with each carrier typically having the same network ID The network and channel IDs can be user programmed during the DAC700 s installation using the NI and CI commands respectively These commands are detailed in the chapter on remote monitor and control operation For single uplinks it is recommended that as a minimum the network I
66. er of cycles the noise level becomes perceptible The degradation process is gradual and depends on the level of the quantizing noise on the original ISO MPEG Layer II II A Functional Description 2 1 5 Table 2 1 2 lists the approximate number of total encode decode cycles before the noise becomes significant Table 2 1 2 Bit Rate and Encode Decode Cycles Number of Mode Bit Rate Cycles Mono 128 kbps 5 64 kbps 1 Dual Mono 384 kbps 15 Stereo 256 kbps 5 Joint Stereo 192 kbps 2 128 kbps 1 These are approximate and the exact number is highly dependent on the source material Postproduction processing effects Modeling postproduction processing of compressed audio is complicated For example an equalizer changes the level of a range of frequencies while limiting and compression are nonlinear processes Very little test data is available to ascertain the effects of postprocessing Private communications with the IRT suggest that ISO MPEG Layer II IIA is robust against the effects of postprocessing and the degree of robustness depends on the compression rate In particular 384 kbps audio is unaffected by postprocessing while 128 kbps audio is somewhat sensitive to postprocessing 2 1 6 ISO MPEG Layer II IIA Functional Description Installation and Initial Startup Overview This chapter describes the steps to install and initialize the DAC700 It also describes the initial configuration procedures as part
67. er to the chapter on remote monitor and control operation LB 0 External Baseband Input Operation In LB 0 an OISO MPEG Layer II ITA stream from an external source is brought in through the broadcast data port and then decoded as shown in Figure 2 18 This mode can be used to monitor the uplink since you are using the DAC700 as a decoder only An independent ISO MPEG Layer II IIA stream can also be sent out the broadcast data port Channel A Analog Input Channel B Digital Audio Control Encoder DSPs Broadcast Data Port J4 Digital Audio Input RS 422 LB 0 Path gt RS 232 RS 485 gt Remote Control F097 A Channel A nalog S Decoder Output DSP Port J1 amp I Channel B 16 y Micro P Controller Closure _ 8 Relay Contacts Ea RS 232 4 pla Async Data User Data Figure 2 18 ISO MPEG Layer II IIA Codec DAC700 Block Diagram for LB 0 2 20 Functional Description and Theory of Operation LB 1 PCM Loopback Operation In LB 1 the data is looped from the output ADC through the DAC as shown in Figure 2 19 bypassing the DSP encoder decoder This mode can be used to verify the ADC performance while bypassing the algorithm LB 1 Path Channel A Analog Input Port J2 Channel B Digital Audio h IA Analog Channe Output Port J1 Channel B Sensor 16 Input Closure _ 8 Contacts RS 232 4 ple Control
68. eturning products please be aware of the following 1 Products returned to ComStream whether for upgrade warranted or out of warranty repair work or maintenance must comply with the ComStream Return Procedure 2 Products shall be forwarded to ComStream transportation prepaid 3 Products returned to ComStream freight collect or without a Return Material Authorization RMA number will not be accepted 4 ComStream shall not accept any responsibility for returned products that are improperly packaged and or damaged in shipment If possible please use original shipping and packaging materials 5 Original product identification markings and labels must not have been removed defaced or altered Further to preserve the warranty the product should not be subjected to abuse improper installation or application alteration accident or negligence in use storage transportation or handling 6 Any returned product shall be completely evaluated in an attempt to duplicate the problem so that appropriate corrective action and repair may be completed Following repair the product shall be thoroughly tested for compliance with appropriate specifications This process will be handled in an expedient and prompt manner but may be subject to available labor and material resources The ComStream warranty as stated herein is in lieu of all other warranties expressed implied or statutory For further information please contact ComStr
69. evant signals are not significant to the human ear and are not required by the information processing centers in the brain The reduction of irrelevance means that these signal components are not transmitted This results in a lower bit rate without any perceived degradation of the audio signal Furthermore it is possible to allow a certain degree of quantizing noise that is inaudible to the human ear due to the masking effects of the audio itself ISO MPEG Layer II I A Functional Description 2 1 1 Every audio signal produces a masking threshold in the ear depending on a time varying function of the signal Masking thresholds are based on masking tones A masking tone is simply a high amplitude audio signal occurring over a relatively narrow frequency span and is often called a masker A number of these masking tones typically occur at several different frequencies in an audio signal A masking tone renders smaller amplitude tones close to it inaudible due to its masking effect The exact shape of the masking effect is called the masking threshold The aggregate of all the maskers defines a global masking threshold The parts of an audio signal below the global masking threshold are inaudible to the ear They are said to be masked and therefore need not be transmitted Other signal components above the masking threshold only require the level of quantization to keep quantization noise below the masking threshold and the quantization indu
70. faults to 38 4 kbps The decoded ISO MPEG Layer II IIA audio data is then sent to both the DAC and AES EBU interfaces The audio is available at both the analog output port and the AUX AES port ISO MPEG Layer IIIA data input to the decoder is selected from two sources a Broadcast data port during external baseband input operation a Audio data encoder when operating in PCM loopback or normal operation mode Loopback testing operation allows the audio data decoder to monitor the functional integrity of the encoder Should the encoder function abnormally or fail the decoder will lose frame synchronization Unit Controller The unit controller provides centralized control of both the encoder and decoder processes The controller utilizes a Motorola MC 68010 running at 12 MHz Included with the microprocessor is 64 K RAM 128 K EPROM and 16 K battery backed RAM within the DAC700 Encoder processor The encoder processor of the unit controller has parallel read write registers to monitor and control the analog and digital AES EBU encoder It also sends numerous event control and status bits throughout the system to select clock rates operating modes and device circuit configurations Decoder processor The decoder processor of the unit controller receives the ancillary data from the decoder DSP This information includes user data and network control messages The information is handled in a manner identical to the encoder processor The
71. h have either failed or are not properly configured Normal Loopback Operation LB 2 In normal operation the data is received from the analog input port encoded then sent out the broadcast data port From the encoder data is also sent to the decoder Normal audio means that the audio transmit and receive sides are operating correctly Abnormal muted or absent loopback audio means that either or both sides are not properlyconfiguredorhavefailed thatis audio dataencoderordecoder ADC orDACcircuits RE Reset Unit This command resets the entire unit and reinitializes all parameters It is identical to a hardware reset Unlike the IN 9346 command the RE command does not reset the nonvolatile parameters This command should be used only if the technician suspects that one or more user defined parameters are incompatible with the unit s physical configuration functional configuration or both Refer to the RE command description in the chapter on remote monitor and control operation for the parameters affected and their default values XM Relay Configuration This command sets or reads the current or existing relay parameters Check the relay input port configuration to determine the current mapping parameters If change is appropriate each contact can be configured independently or in combination with other contacts by the relay control messages from the unit controller Maintenance and Troubleshooting 6 3 Fault Condition Desc
72. he DAC700 unit to an external portable terminal or desktop computer The computer is used to issue user control configuration and diagnostic commands to the unit The computer can also be used to monitor unit operating status and fault and alarm information The M amp C port supports a standard RS 232 interface or an optional RS 485 interface a The standard RS 232 interface provides duplex asynchronous serial data with an operating range from 300 1200 2400 4800 9600 to 19200 bps The defaults for an RS 232 interface are 1200 bps odd parity 7 data bits and 1 stop bit a The RS 485 interface provides duplex asynchronous multidrop packet data configured for party line operation This port is used in conjunction with the remote control computer The operating rates are 300 1200 2400 4800 9600 or 19200 The RS 485 interface defaults are 2400 bps odd parity 7 data bits and 1 stop bit A proprietary ComStream packet protocol is used for communicating via this interface See the chapter on ComStream packet protocol The default RS 485 address of the M amp C port on the DAC700 is 31 but it can be configured to any bus address from 1 to 31 using the RA command See the chapter on remote monitor and control operation Installation and Initial Startup Initial Power Up Installation Check Relay Control The relay control port is a multifunction interface that supports 16 TTL opto isolated sensor inputs and eight
73. he desired change s This information will allow a ComStream Customer Service representative to provide a formal quote for the upgrade 5 Include a purchase order PO for any upgrade or out of warranty repair work being performed ComStream will begin repair work after a PO is received 6 Reference the RMA number on all paperwork that accompanies the equipment and write the RMA number clearly on the outside of the shipping container 7 Ship your module in the original shipping carton and packaging or its equivalent prepaid to the following address ComStream 6350 Sequence Drive San Diego CA 92121 2724 USA RMA Number Do not include product accessories such as I amp O guides or rack mount brackets When handling or shipping static sensitive equipment observe antistatic procedures and always use antistatic bags for shipment Upon request ComStream will provide you with ESD bags for your use Preface Revision History Customer Support All equipment upgrade and repair requests will be completely evaluated and the required work performed in an expedient and prompt manner The equipment will then be thoroughly tested for compliance with appropriate specifications This guide is periodically updated and revised For documentation updates call ComStream Customer Service located in the United States at 619 657 5454 toll free 888 559 0831 or fax your request to 619 657 5455 Revision Date Type of Revision Rev
74. he presets are controlled by the three TTL input lines on the AUX AES port P3 The mappings of these pins to the preset definitions are as follows Preset No Pin 3 Pin 4 Pin5 1 0 0 0 2 0 0 1 3 0 1 0 4 0 1 1 5 1 0 0 6 1 0 1 7 1 1 0 8 1 1 1 4 18 Remote Monitor and Control Operation PP PS Data Port 2 Configuration Passthrough Use this command to set or read the data port 2 configuration Syntax PP lt baud gt lt parity gt lt data_bits gt lt stop_bits gt Parameters Valid lt parameters gt are as follows a lt baud gt 300 1200 2400 4800 9600 a lt parity gt O E N odd even none a lt data_bits gt Tors a lt stop_bits gt lor2 a Defaults 2400 0 7 1 Preset Selection Use this command to set or read the current preset Syntax PS lt parameter gt PS Parameters The valid lt parameter gt range is 1 through 8 The default is 1 Additional Information If preset mode 1 then this command is read only and reports back the current hardware preset selection number When a preset is selected the associated preset definition parameters are loaded into their respective command values for unit reconfiguration Remote Monitor and Control Operation 4 19 PT Passthrough Mode Use this command to set or read the passthrough mode Syntax PT lt parameter gt PT Parameters Valid lt parameter gt values are a 0 default disables mode a enables
75. his guide may differ slightly from those shown on your front panel display or computer console due to variations in your system setup configuration or customization Preface ix Keyboard Entries Each activity or task is presented in a series of numbered step by step instructions Commands or information that you type into the system appear in a different bold type Type ST and press Enter Keys that are pressed in combination appear with a plus sign For example Ctrl Shift 3 You hold down the Control and Shift keys and press the number 3 Mouse Actions You may be using a mouse to interact with your system The conventions used in this guide are a Click Click the left mouse button a Double click Click the left mouse button twice in rapid succession a Drag Click and hold the left mouse button then move the selected object with the mouse Preface Warranty Statement ComStream warrants that its products are free from defects in material and workmanship at the time of shipment and that they conform to applicable specifications In no event will ComStream be liable for consequential misuse or damages The ComStream DAC700 Codec Multiplexer is warranted against any above mentioned defects that appear within one year of shipping date Should it be necessary to make a claim against this warranty the buyer shall first notify ComStream s Customer Service Department to define the nature of the problem When r
76. illary Data Rate Configuration Ancillary data is made up of three components relay blocks network control message blocks and user data blocks Each of these information types has a specific packet structure or format Relay blocks include the input relay information the network ID and channel ID information These blocks have the highest priority of the three Relay blocks are sent out at user programmable intervals in multiples of 100 ms The length of the interval is programmed in the DAC700 with the RM command See the chapter on remote monitor and control operation a Network control message blocks contain commands generated by the ANMS and sent to the receivers through the satellite transmission Network control messages have the second highest priority a User data blocks are originated by the user and input into the DAC700 for broadcast transmission to all receivers The ancillary data rate is the bandwidth set aside for this information and is programmed using the AG command The bandwidth is dynamic and is only as wide as it needs to be The default is 38 4 kbps The rule of thumb is to minimize the user data rate as much as possible Because user data can vary from 300 to 9600 bps at lower transmission rates 112 kbps down to 56 kbps audio degradation may occur if user data exceeds roughly 5 of the bandwidth Installation and Initial Startup 3 9 Judging the effect that data bandwidth has on music quality
77. illary data packets with the digital audio into a composite stream This composite data is then output via the broadcast data port as shown in Figure 2 9 The data block length can be user defined with the BL command Valid lengths are from 30 to 255 bytes with a system default of 26 bytes For more information on block types refer to the chapter on installation and initial startup The ABR200 75 can only accept block lengths of up to 50 bytes Blocks are closed and transmitted based on one of the following a Maximum block length When the maximum block length is reached the current block is transmitted via the broadcast data port a Time out If the maximum block length has not been reached in a given period of time the block is closed and transmitted The length of time is called the user data block time and is user defined a Termination character The user may define a special end of block terminating character which may also be sent with the user data or stripped off Data port channel 1 features are programmed with the Data Port 1 Configuration UC User Block UB and User Termination UT commands See the chapter on installation and initial setup Functional Description and Theory of Operation 2 11 On the receive side composite data is demultiplexed by the audio data decoder DSP 4 into separate digital audio and ancillary data streams The ancillary data is transferred to the unit controller where it is
78. ing the terminal emulation program enter LB 1 to put the unit in PCM loopback mode Allow the unit to operate in loopback for 5 to 10 minutes error free There are also two other loopback modes available Select the appropriate mode for your testing See the chapter on functional description and theory of operation b After operating in loopback mode enter FL and check for any fault codes e If no faults are displayed enter LB 0 to put the unit into normal operating mode e If any faults are displayed refer to the chapter on maintenance and troubleshooting Installation and Initial Startup Firmware Version Initial Configuration 3 Check audio performance a Using the terminal emulation program enter the AT command with the appropriate parameter The DAC700 provides two internally generated audio test tones for checking audio performance and the option of checking the left channel the right channel or both See the remote monitor and control operation chapter b After checking audio performance enter AT O to return to normal operation Check the firmware version number as part of the initial installation The number should be the same as all other stations in the network Different version numbers indicate possible software incompatibility and might result in unusual or intermittent operation 1 Enter DC 2 Verify that the firmware version number matches the version number of other stations in the
79. ion Glossary FDM Hz ID IEC ISO IXC kbps kHz LED LNA LNB Loopback M amp C MHz MPEG MR Network Control Message Blocks Normal Operation LB 2 Frequency Division Multiplexing Hertz Identification International Electrotechnical Commission International Standards Organization Interexchange Carrier Thousand bits per second Thousand Hertz Light Emitting Diode Low Noise Amplifier Low Noise Block downconverter A type of diagnostic test in which the transmitted signal is returned to the sending device after passing through the DAC700 This enables a technician to compare the output signal with the input signal to get some sense of what is wrong The DAC700 has two diagnostic loopback modes PCM loopback and network loopback For more detail see the definitions of the specific loopback modes Monitor and Control Megahertz million Hertz Motion Picture Experts Group Master Reset Network control message blocks are one of three types of ancillary data processed by the DAC700 Network control messages consist of commands generated by the ANMS computer and sent to the receivers in the transmission Of the three types of data network message blocks have the second highest priority In normal operation the data is received from the analog input port encoded and then sent out the broadcast data port From the encoder data is also sent to the decoder Glossary 3 Passthrough Mode PC PCM
80. ire unit and reinitializes all volatile parameters but it does not reset the nonvolatile parameters Remote Monitor and Control Operation 4 13 LB Loopback Mode Use this command to set or read the codec loopback mode Syntax LB lt loopback mode gt LB Parameters Valid lt loopback mode gt values are as follows a 0 External baseband input operation a 1 PCM loopback a 2 Normal operation default Additional Information In external baseband input operation an ISO MPEG Layer II IIA stream from an external digital audio is brought in through the broadcast data port and decoded From the decoder data is sent to the DAC700 converted to analog audio and sent out the analog output port An independent ISO MPEG Layer II IIA stream can be sent out the broadcast data port In the PCM loopback operation analog audio is converted into 16 bit linear PCM data and transferred directly from the analog to digital converter output to the digital to analog converter input The PCM data is processed through the DAC700 converted into analog audio and sent to the analog output port In the normal operation analog audio is converted into 16 bit linear PCM data and transferred directly from the audio data encoder output to the decoder input The PCM data is processed through the decoder converted into analog audio and sent to the analog output port 4 14 Remote Monitor and Control Operation LR MU Left
81. l fault code Encoder DSP alarm code Decoder DSP alarm code Action Ensure the unit is plugged into an active AC outlet m Verify that the line cord is firmly plugged into the rear panel receptacle Ensure the line cord is not at fault by using a known working cord This indicates that the analog audio input level exceeds 18 dBu Restore input audio to normal peak level This is a summary alarm that means one or more faults have occurred Use the FL command FL to determine what faults are occurring For each fault identified refer to the fault description and suggested actions presented in this table Ensure the audio is normal Ensure the unit controller has not exceeded the watchdog time out and that the processor memory is functioning normally Ensure the transmit PLL reference is present in phase and within the 25 Hz limit Ensure that the receive PLL reference is present in phase and within the 25 Hz limit Check the timing source a If the internal source 12 288 MHz crystal controlled oscillator master clock is being used switch to an external timing source a Ifan external source is being used for send timing ST or receive timing RT switch to an internal timing source This indicates the audio digital decoder has lost frame synchronization because the encoder output is abnormal intermittent or has failed This indicates analog audio input to the left channel exceeds the 18 dBu maximum le
82. lid lt mode gt values are a 0 Simplex mode a l Full duplex mode default DM should be set to 0 simplex if PP is set to a rate more than 9600 for Passthrough Additional Information In duplex mode the DAC700 encodes and sends the digitally compressed data out and loops it back through its onboard decoder The signal is then available as needed in monitoring In simplex mode the DAC700 encodes and sends the digitally compressed data out without looping this information back through its onboard decoder 4 12 Remote Monitor and Control Operation FL Fault Status Use this command to display accumulated faults Syntax FL Additional Information The faults are bit mapped registers with each bit and associated weight assigned to a particular fault condition The output value is the sum of all set fault weights The table below provides a description of each fault and its weight If the Audio Overload Left Channel and Audio Overload Right Channel are active the FL command returns the value 24 Fault Condition Weight Encoder PLL not locked 1 Decoder PLL not locked 2 Decoder not framed out of sync 4 Audio Overload Left Channel 8 Audio Overload Right Channel 16 Network or channel ID fault 32 Master Reset Use this command to reset nonvolatile parameters to their factory default settings See Table 4 3 Syntax IN 9346 Additional Information A related command RE resets the ent
83. lows a lt baud gt 1200 2400 4800 9600 a lt parity gt O E N odd even none a lt data_bits gt Tor8 a lt stop_bits gt lor2 a Defaults 1200 0 7 1 4 16 Remote Monitor and Control Operation PD Preset Definition Use this command to set or read the preset definition lt preset_number gt identifies each unique definition Syntax PD lt preset_number gt lt network_id gt lt channel_id gt lt encoder_mode gt lt timing gt lt ag_value gt lt transmit_channel_rate gt lt receive_channel_rate gt PD Parameters The valid lt parameter gt range of preset numbers is 1 to 8 The default is 1 1 1 1 0 38400 128000 128000 Additional Information The preset definition can be used to preset the configuration parameters for each channel into the DAC700 for that channel To do this the user defines the configuration for each channel using the PD command then assigns the preset definition for that configuration to a particular DAC700 using the Preset Select PS command The preset definition can also be used in redundancy protection In redundancy protection an extra DAC700 and modem pair serves as a backup to any one channel of a DAC700 and modem pair When a user defined fault is detected a channel switchover automatically occurs This switch initiates the replacement of the faulty channel s DAC700 and modem pair with the spare DAC700 and modem pair Switchovers are controlled by the Preset Mod
84. lt specified by lt parameter gt in the fault history register Syntax CF lt parameter gt Parameters The default is 0 If lt parameter gt 0 all faults are cleared Channel ID Use this command to set or read the channel ID number that is sent out as part of the relay control message Syntax CI lt parameter gt CI Parameters Valid lt parameter gt range is 1 through 255 The default is 1 Additional Information For a description of the channel ID refer to the chapter on functional description and theory of operation Remote Monitor and Control Operation 4 7 CM Contact Map Use this command to allow the codec to be configured to provide a mapping of relay contacts at the transmitting codec to relay contacts at all receiving decoders both internal and over the satellite network Syntax CM lt map values gt CM Parameters The map is a series of eight parameters separated by commas which indicates a correspondence of transmitting relays to receive relays The mappings are designated by decimal integer values The first transmitting relay designator corresponds to receive relay 1 the second corresponds to receive relay 2 etc through receive relay 8 Additional Information CM 3 2 1 4 15 6 6 7 performs the relay mapping as follows Transmitter Receive Relay Relay 3 1 2 2 1 3 4 4 15 5 6 6 6 7 7 8 The default is 1 2 3 4 5 6 7 8 Remote Monitor and Control O
85. mand syntax is XM active_input_mask polarity_mask debounce Network and Channel Definitions Define channel and network ID numbers as follows 1 Define channel ID numbers The command syntax is CI n 2 Define network ID numbers The command syntax is NI n Timing Source Configuration The DAC700 uses the timing reference to support independent asynchronous transmit and receive operations The correct timing source is essential for accurate unit internal timing and external interface timing For more information on timing sources see the chapter on functional description and theory of operation To select the timing source use the TT command as shown below a TT O0 to select internal 12 288 MHz crystal oscillator TT 1 to select external from send timing a TT 2 to select external from receive timing a TT 3 to select AES EBU timing input Installation and Initial Startup 3 11 COMSTREAM A Spar Company 3 12 Installation and Initial Startup Overview Command Syntax Remote Monitor and Control Operation The DAC700 M amp C port provides a means to configure and monitor the status of the entire ISO MPEG Layer IIIA audio codec multiplexer unit The unit is capable of communicating in RS 232 ASCII message format and in a multidrop RS 485 network packet protocol format When operating in the RS 485 packet protocol format network control messages can also be communicated through this p
86. mentary grade 2 1 3 contribution grade 2 1 3 distribution grade 2 1 3 emission grade 2 1 3 quality vs bit rates 2 1 4 Firmware version checking as part of installation 3 7 G Global masking threshold 2 1 2 l Indicators fault 6 5 6 7 overload 6 4 6 7 power 6 5 6 7 Initial power up 3 5 Installation check establishing communication with DAC700 3 6 performing the check 3 6 testing for faults 3 6 ISO MPEG Musicam data block 2 1 4 testing 2 1 4 ISO MPEG Layer N HA 2 1 1 J J1 A 3 J2 A 3 J3 A 3 J4 A 3 J5 A 3 J6 A 3 J7 A 3 L Location requirements 3 2 Loopback modes 2 20 LB 0 2 20 LB 1 2 21 LB 2 2 22 LB Command 4 14 use in troubleshooting 6 3 M M amp C interface 2 14 M amp C port A 4 description 3 4 interface pinout B 6 M amp C interfaces 2 14 Network data interfaces 2 10 port number A 3 Masking threshold 2 1 2 calculation 2 1 2 Masking tone 2 1 2 Mechanical specifications A 5 N Network ID defining network ID numbers 3 11 proper signal discrimination 2 5 P Passthrough data 2 12 2 13 Passthrough mode 2 12 configuration configure data port 2 3 9 enable mode 3 9 Performance monitoring checking audio performance 6 2 checking relay contacts 6 2 isolating system faults 6 3 listing current parameters 6 2 reset and reinitialize unit 6 3 set or read current relay parameters 6 3 Power specifications A 5 Power module 2 20 R Rear panel mapping A 3 ports A 3 Relay control interface 2 1 2 14
87. mote Control Figure 2 6 DAC700 Functional Block Diagram F094 2 8 Functional Description and Theory of Operation Audio Input Interfaces Analog audio is input as two channels A B through the analog audio input port as shown in Figure 2 7 The audio is buffered amplified and converted into 16 bit linear PCM data by the Analog to Digital Converter ADC The ADC is a dual channel oversampling device operated at a 48 kHz sample rate Predigitized AES EBU audio may also be input through the AUX AES port from an external device Input AES EBU data rates of 56 K and 112 K are not supported The AES EBU serial audio data is converted into multiplexed 16 bit linear PCM data compatible with the ADC output The audio data is sent to the audio data encoder DSP 1 DSP 2 A 2 1 selector controls which audio data source is input either via the ADC from analog audio input port or the AES EBU interface from the AUX AES port Selector operation is controlled by the unit controller The audio data encoder DSP 1 DSP 2 converts the audio data to ISO MPEG Layer II IA digital audio The audio data then goes to the data multiplexer DSP 3 where ancillary data is added to form a composite stream that is transmitted via the broadcast data port to the modem Audio Analog Analog Analog to Data Broadcast RS 422 Audio In Input Digital Encoder Data Port Sync Channel Port J2 Converter DSP 1 J4 ISO M
88. n ISO MPEG Layer IIIA frame is protected by an error protection polynomial and provides the ability to detect errors that occur in the header The data portion of the frame is unprotected and any error occurring in the data part of the frame remains The ISO MPEG Layer II IIA system has a defined error strategy If an error is detected in the header the last frame 24 ms of audio is repeated If in the succeeding frame an error is detected in the header the second and all succeeding frames with errors are muted This error mitigation technique has been shown to be effective for bit error rates of approximately 10 This error rate represents error rates easily achievable by transmission systems Using this strategy there is a smooth degradation of the audio quality as the error rate increases until the error rate becomes excessive At the point of excessive error rates the audio output mutes Tolerance to multiple processing To understand the effect of multiple encode decode cycles it is important to review the predominant effect that allows ISO MPEG Layer II IIA audio to achieve its compression This is the hiding of quantization noise under a loud signal ISO MPEG Layer II IIA audio adjusts the degree of quantization induced noise in each subband and thus hides more noise uses fewer bits in the subbands that contain large amounts of audio energy The quantizing noise raises with each encode decode cycle and after a sufficient numb
89. nalog bandwidth The command format is AB 0 to select bandwidth A AB 1 to select bandwidth B AB 2 to select bandwidth C AB 3 to select bandwidth D 2 Set the encoder transmit mode The command format is TM 0O to select mono TM 1 to select dual mono TM 2 to select joint stereo 3 Set the encoder transmit rate The command format is TD transmission_rate Replace transmission_rate with 56000 to select 56 K 64000 to select 64 K and so on 4 Set the decoder receive channel rate The command format is RD receive channel rate The value for receive channel_rate should be the same as for transmission _ rate User Data Configuration Use the following steps to configure the user data feature 1 Configure data port 1 The command format is UC baud parity data_ bits stop_ bits 2 Set the user data time or send interval The command format is UB time _interval 3 8 Installation and Initial Startup 3 Set the user data termination character The command format is UT termination_character Replace termination_character with the decimal value of the ASCII character to be used Passthrough Mode Configuration Use the following steps to configure the passthrough mode 1 Configure data port 2 The command format is PP baud parity data_bits stop_bits 2 Enable the data passthrough mode using the PT command as shown PT 1 to enable data port 2 PT 0 to disable data port 2 Encoder Decoder Anc
90. ne or both audio input channels are above 18 dBu Clipping of the input audio channels occurs at 18 dBu and higher For more information on overload refer to the chapter on maintenance and troubleshooting The Fault indicator illuminates red when a decoder or encoder fault condition exists Examples of such conditions are Receive Rx or Transmit Tx Phase Lock Loop PLL out of lock and Digital Signal Processor DSP hardware errors such as memory fault watchdog time out or muted audio Functional Description and Theory of Operation 2 3 The fault indicator function mimics the alarm relay and is masked using the alarm mask AM command For more information see the chapter on remote maintenance and control operation Transmission Channel The ComStream digital audio satellite broadcast system uses a single RF carrier to Signal Format distribute audio data relays and control information from the uplink to all downlinks This multiservice data stream uses time division multiplexing TDM to receive process and transmit all these types of information Multiple audio channels can be transmitted using an RF carrier for each mono dual mono stereo or joint stereo channel service This technique is known as frequency division multiplexing FDM Signal parameters between two RF carriers can be completely different One carrier may be operating monaural audio at 64 kbps using Quadrature Phase Shift Keying QPSK modulation and a se
91. network If the number does not match notify the network operator or ComStream Customer Service as soon as possible Specify the initial configuration parameters for the DAC700 using the procedures that follow Use only the procedure or procedures that support your hardware configuration and the operating mode or modes you intend to use in the network The configuration process requires you to use a number of commands This section gives the general syntax for commands used during configuration An alphabetical listing of all commands with a full description of the command command syntax valid parameters and default values is provided in the remote monitor and control operation chapter Read the command description in the remote monitor and control operation chapter before using the command to configure the DAC700 Audio Bandwidth Configuration The audio bandwidth configuration depends on three factors a Transmission rate Operating mode mono dual mono stereo joint stereo a User selectable bandwidth For information on the relationship between these factors see the appendix on technical specifications and port information Installation and Initial Startup 3 7 From the information in that appendix select the transmission rate operating mode and bandwidth for the audio configuration of your network To configure the unit audio bandwidth to match your selections perform the following steps 1 Set the encoder a
92. nitor and control port configuration sets Preset definition for redundancy protection Preset mode sets Data port 2 configuration passthrough Preset selection Passthrough mode Remote port address sets RS 485 control device Remote control port configuration sets RS 485 M amp C Receive channel rate data Resets the unit Relay message interval selects Real time status fault Transmit channel rate data Set protection mode Encoder transmitter mode Select ISO MPEG Layer II IIA Transmit timing selection clock source Relay data in band signaling User data time or send interval Data port 1 configuration user data User termination Relay mapping input AT LR and MU affect only DAC700 decoder audio function Remote Monitor and Control Operation 4 3 Detailed Command Descriptions AB Following is a list of commands with a detailed description of each used to configure and operate the DAC700 The items shown in italics are variable characters to be replaced by the specific parameter information being entered Because of space constraints defaults sometimes appear on more than one line In actual use these defaults would be on one line separated by commas Analog Bandwidth Use this command to set audio bandwidth Syntax AB lt bandwidth gt Parameters lt bandwidth gt parameters are as follows a 0 Bandwidth A default a 1 Bandwidth B a 2 Bandwidth C a 3
93. nsmitting end At the default sampling rates pulsed signals are reproduced faithfully to the nearest 50 ms Audio Data Encoder The audio data encoder DSP 1 DSP 2 consists of two DSPs that perform transmit audio ISO MPEG Layer II IIA processing The first DSP handles the left channel and the second DSP handles the right channel of both the analog and digital audio inputs These two DSPs convert the audio data into 16 bit linear PCM data and transfer it to the data multiplexer DSP 3 for further processing via a shared memory architecture Functional Description and Theory of Operation 2 15 Data Multiplexer The data multiplexer DSP 3 inputs and processes 16 bit linear PCM audio data and asynchronous ancillary data from the encoder processor Data transfer is via a simplex interface that operates at a programmable rate set by the unit controller The ancillary data is multiplexed along with the 16 bit linear PCM audio data into a composite data stream The composite data is then transferred synchronously via the RS 422 network interface for transmission by the CM701 modem over the satellite link Audio Data Decoder DSP 4 performs the onboard ISO MPEG Layer IIIA decoding of the received loopback or external digital stream A single DSP demultiplexes the incoming composite data stream into 16 bit linear PCM audio data and asynchronous ancillary data The ancillary data is output to the unit controller via a simplex interface that de
94. ntrol commands have the following structure XXX parameter ComStream Packet Protocol Status Query Commands The structure of a status query command consists of a Two or three letter mnemonic ASCII string associated with the parameter to be interrogated a Single ASCII space character a ASCII question mark character Status query commands have the following structure XXX Command execution Commands are executed when the following conditions are met Command is valid a Parameter value when required is within the valid range a Parameter value or command is compatible with the present modem configuration Command or query can be executed immediately Commands that do not follow these guidelines are not executed and produce an error code For information on error conditions and valid command parameters refer to the chapter on remote monitor and control operation Controller Packet Command Example To assist you in creating and sending viable packets a byte by byte packet construction for the query command EM is presented in this section This EM query packet is constructed by the controller and issued to a slave modem The following assumptions are made for this example a Slave address is 1 a Extended addressing is not required a Acknowledgment packet is required a ASCII codes used in this example include a 6Eis45y o Mis4Dr a space character is 204 o is 3Fy ComStream Packet Protocol 5 5
95. o isolated inputs DB 37 female RS 232 asynchronous or RS 485 multidrop packet address is configurable from control port default is address 31 default interface is RS 232 no handshaking signals DB 9 female Unit configuration status and diagnostics connects to terminal emulator RS 232 or ComStream packet protocol RS 485 A 4 Technical Specifications and Port Information Front Panel LED Status Mechanical IDU Power Environmental The front panel LED descriptions are shown in Table A 3 Table A 3 LED Descriptions Label Function LED Color Power Power on Green Audio Sync Decoder framing OK Green Dual Mono Audio mode Green Joint Stereo Audio mode Green Overload Left right audio overload Red Blank Fault status Red Size 4 5 cm x 42 5 cm x 38 cm 48 cm rack mount 1 75 x 17 x 15 19 rack mount Weight lt 6 kg 12 lbs Shipping Weight lt 11 kg 24 lbs Input Voltage AC 90 to 264 VAC auto ranging Frequency 47 to 63 Hz Consumption lt 40 watt typical Temperature 0 to 50 C operating Humidity 0 to 95 noncondensing Safety UL 1950 CSA 950 and TUVPS EN 60950 Emission FCC Part 15B Class A CISPIR 22 Class B Technical Specifications and Port Information A 5 COMSTREAM A Spar Company A 6 Technical Specifications and Port Information Interface Pinouts Analog Output Port J1 The pin positions for the analog output port connector are given in Figure B 1 00000 00
96. of the installation process The overall steps for installing and starting up the DAC700 are shown in Table 3 1 as well as the recommended installation sequence You should become familiar with this sequence before installing the unit Be aware of any unusual conditions or contingencies that might affect the installation process Table 3 1 Installation Sequence Sequence Site planning and preparation Location requirements Safety considerations External connections Initial power up Installation check Firmware version Initial configuration Audio bandwidth configuration User data or passthrough mode configuration Encoder decoder ancillary data configuration User relay configuration Network and channel definitions Timing source configuration Site Planning and The purpose of site planning is to specify where the components are to be located Preparation and to identify any special installation or operational requirements Time spent in site planning prevents unnecessary complications during installation Installation and Initial Startup 3 1 Location Requirements Mounting the DAC700 External Connections Location requirements for the DAC700 unit are Standard 19 inch equipment rack one unit 1 75 inch high Adequate ventilation Mount the DAC700 in a manner that ensures adequate ventilation at all times The minimum airflow clearance space required is three inches at the sides and six inches in the rear Fa
97. on 2 17 For internal timing TT 0 the DAC700 uses its onboard 12 288 MHz PLL to generate the terminal timing that is sent to the modem with the transmit data Figure 2 14 illustrates the internal timing source DAC700 Modem 12 288 MHz Analog Audio y Terminal Timing TT L de Tx Data R DAC700 Int timing Modem Ext timing F112 04 Figure 2 14 TxCLK Internal Timing PLL For send timing TT 1 the DAC700 uses the clock received from the modem to send back with the transmit data This clock is derived from the modem s onboard PLL as shown in Figure 2 15 DAC700 Modei Terminal Timi Analog Audio erminal Timing L Tx Data L Send Timing SUL R DAC700 Ext timing Modem Int timing F113 04 Figure 2 15 Send Timing 2 18 Functional Description and Theory of Operation For receive timing TT 2 the DAC700 uses the clock received from the modem to send back with the transmit data This clock is derived from the active demodulator on the modem as shown in Figure 2 16 DAC700 Modem Terminal Timing Tx Data Receive Timing De modulator DAC700 Ext timing Modem Derived timing F114 04 Figure 2 16 Receive Timing For AES EBU timing TT 3 the DAC700 derives the clock from the AES EBU digital input data stream and sends this to the modem with the transmit data as shown in Figure 2 17 DAC700 Modem AES EBU Digital Data Terminal Timing Tx Data DAC700
98. onous Receiver Transmitters UARTs are used to implement the data port One UART is used for user data and a separate one is used for passthrough data Functional Description and Theory of Operation 2 13 Monitor and Control Interface The monitor and control interface provides two ports for external monitoring and control of the DAC700 configuration and operation This interface supports both RS 232 and RS 485 asynchronous channels via the M amp C port The DAC700 connects via the M amp C port to an external portable terminal desktop computer or terminal emulator Control and status information from the remote computer is input to the unit controller encoder decoder processors as shown in Figure 2 11 Encoder Processor Control Status M amp C Alarm To Terminal Unit Gomraller Port J6 Desktop Computer Terminal Emulator Control Status From Terminal Desktop Computer Terminal Emulator Decoder Processor F075 Figure 2 11 Monitor and Control Processing Relay Control Interface The relay control interface supports 16 TTL opto isolated sensor inputs that are used to create the relay control messages broadcast to the network in the ancillary data stream These 16 relay inputs are mapped to eight output relays at each audio decoder within the network this is on both the audio receivers and the DAC700 The relay contacts can be used to control external audio or other station equipment Because only eight c
99. ontact closures are available on each audio decoder a mapping must be made as to which of the 16 possible control inputs activate the closures For the DAC700 decoder this mapping is performed by using the contact mapping CM command see the chapter on remote monitor and control operation The default for both the DAC700 and the ABR audio receiver decoders is to have the first eight inputs control the eight closures 2 14 Functional Description and Theory of Operation Figure 2 12 illustrates the 16 to 8 mapping function that occurs for the relay control of the DAC700 decoder section DAC700 MUX DAC700 ABR200 ABR75 TDM Closure 1 Control Cue Channel Input Sampling F077 Figure 2 12 Contact Mapping Diagram The sensor inputs operate at TTL logic levels internally pulled up to 5 volts The inputs become active by providing a dry contact closure to the signal ground on the relay control port Contact polarity can be set as either normally open or normally closed for each relay All inputs are sampled at a user defined rate set using the RM command see the chapter on remote monitor and control operation Any change in the state of any input line is sensed within two sample periods and transmitted over the control channel The input levels are transmitted continuously over the control channel at a specified rate The relay contact closures at the receiving end directly track the logic levels at the tra
100. ooting the DAC700 unit For general troubleshooting perform the following steps 1 Check the status and fault indicator lights on the unit front panel for any alarms Using the remote control computer check the fault display for any unit fault codes Check for any fault indications in associated system equipment such as the modem ABR receiver s RT terminal control console event sequencer etc Check for any facility services faults such as AC line power surge drop brownout or loss excessive temperature or humidity conditions in equipment room or enclosure air conditioning cooling fans or blowers not operating dirty or blocked air filters etc 6 6 Maintenance and Troubleshooting Unit Troubleshooting Table 6 3 provides a list of faults with the probable cause and corrective action that applies to the DAC700 unit The remote control computer laptop terminal or terminal emulator is required to make full use of the troubleshooting information in the table The status and fault indicators on the front panel should be used in conjunction with the remote control computer Table 6 3 DAC700 Unit Troubleshooting Fault Indication Power indicator light green is off Overload indicator light red is on Fault indicator light red is on Tx PLL unlock fault code Rx PLL unlock fault code Decoder not framed fault code Audio overload left channel fault code Audio overload right channe
101. or the audio user data and relay control ports This can be accomplished by communicating with a receiver locked to the uplink RF carrier or using an ASCII terminal to query the decoder section of the DAC700 to confirm the setup and perform several diagnostic tasks Installation and Initial Startup 3 5 Use the DB 9 to DB 25 adapter cable ComStream Part No 30 0120 093 to connect the DAC700 s M amp C port to the DB 25 connector on your terminal The terminal should be configured for 2400 baud 7 data bits 1 stop bit and odd parity When communication is successfully accomplished a gt prompt appears on the terminal indicating it is ready to accept commands To establish communication with the DAC700 a Atthe ASCII terminal connected to the DAC700 press the Enter key on the terminal The DAC700 should respond with an ASCII login request string For an alphabetical listing of commands with proper command syntax valid parameters and default values refer to the chapter on remote monitor and control operation Once the communications link with the DAC700 is established use the following steps to perform the installation check 1 Using a terminal emulation program verify that the default values are correct by entering the appropriate command for each value For a list of the commands and their correct values see the chapter on remote monitor and control operation 2 Test for fault free operation a Us
102. ort The command formats are compatible with existing ComStream command formats However for RS 232 operation there is no need for an Escape character to precede the command If an Escape character is input by the user it is ignored and the command executes as entered For RS 232 ASCII commands the following generic formats are used a To write or change a parameter associated with the command designated by a two character mnemonic XX the formats are o XX parameter a XX parameter 1 parameter 2 parameter 3 Separate multiple parameters with a comma only do not add spaces a To read or query a parameter value for command the format is no XX The space before the question mark is optional a To repeat the previous command use a carriage return only a To access help press Help provides a summary of available commands with a short explanation of each Commands may be entered in either upper or lowercase All commands are followed by a carriage return Remote Monitor and Control Operation 4 1 Command Error Codes Command errors occur when a command has been mistyped is inappropriate or cannot be immediately executed The operator normally receives one of the error messages shown in Table 4 1 Table 4 1 Error Codes and Descriptions RS 232 Mode Invalid Command Invalid Parameter Not Available RS 485 Mode Description ER1 Indicates that an invalid command has been entered ER2 Indicates that the a
103. peration co ca Relay Contact Control Use this command to allow the receive relays to be temporarily activated deactivated for test purposes Syntax CO lt string gt CO Parameters The lt string gt in the command line is an 8 byte character string that controls the state of each relay contact The first character controls relay number 1 the second controls relay number 2 etc through relay 8 Valid lt string gt values are as follows a 0 Deactivates a relay a Activates a relay a X Do not care normal control channel processing The default is XXXXXXXX Additional Information This command is implemented before the relay sense command processing thereby permitting a logical control of the contacts not physical contact closure Contact Status Query Use this command to query the physical state of the relay contact closures Syntax COQ 7 Additional Information The value returned is an eight character value each character representing the status of an individual relay The first character corresponds to the first relay the last character corresponds to the last relay A 0 for a relay indicates that the relay is open a 1 indicates that the relay is closed Remote Monitor and Control Operation 4 9 cs DC Contact Sense Use this command to control the normal deactivated position for the DAC700 decoder relay closures Syntax CS lt string gt CS Parameters The lt st
104. r II IIA has been demonstrated to be a superior compression algorithm The importance of the audio compression algorithm is the direct relationship between the low bit rates associated with compression and the costs associated with the transmission and storage of compressed audio The bit rate for high quality stereo audio signals 1 411 kbps for a CD can now be reduced by the Musicam algorithm to about 200 kbps as a result of major progress in the development of source coding techniques which utilize knowledge of the human ear This means that the average quantization of the audio signal at a sampling rate of 48 kHz would be approximately 2 bits per sample in the mono channel instead of the 16 bits per sample used in CDs Despite this high reduction in the bit rate no quality differences are discernible to a trained ear A slight impairment only becomes audible at higher compression rates ISO MPEG Layer IT IIA also offers the flexibility of independently adjustable digital bit rates 56 kbps 64 kbps 112 kbps 128 kbps 192 kbps 256 kbps 384 kbps etc as well as embedded data user data within the audio bit stream Compression Concepts The main principle of ISO MPEG Layer IIIA is the reduction of redundancy and irrelevance in the audio signal Every audio signal contains irrelevant signal components such as determination of timbre and localization which have nothing to do with the identification of the audio signal These irrel
105. r reserves the right to make any changes in any products or parts thereof described herein without notice Copyright 1998 ComStream Corporation This digital audio receiver is manufactured by ComStream Corporation It incorporates Musicam compression technology under license from Corporate Computer Systems Inc as outlined in the copyright notice below This Musicam digital audio product is manufactured under license from Corporate Computer Systems Inc This product contains one or more programs protected under International and U S copyright laws as unpublished works They are confidential and proprietary to Corporate Computer Systems Inc They may not be in whole or in part reproduced decompiled reverse engineered analyzed copied translated or used to create derivative works Copyright 1992 1993 1994 1995 by Corporate Computer Systems Inc All rights reserved Musicam is a registered trademark of Corporate Computer Systems Inc 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 radiates radio frequency energy and if not installed and used in accordance with the instruction guide may cause harmful interference to radio communications Operation of this equipment in
106. receives either analog audio or Audio Engineering Society European Broadcast Union AES EBU input from a studio sound source and translates it to digital audio A user data port can be connected to a personal computer so that information such as air logs or station traffic can be transmitted with the audio signal The unit can also transmit relay control information to the network of ABR receivers When used with ComStream uplink racks the unit provides a protection mode that allows it to shadow and swap out channels even if they operate at different encoding and transmission rates Figure 1 3 DAC700 Audio Codec Mux Unit Several capabilities give the DAC700 unmatched versatility for audio and data distribution The DAC700 a Isa full duplex multirate ISO MPEG Layer IIIA encoder and decoder that can transmit and receive mono dual mono stereo or joint stereo analog audio a Provides full duplex selectable AES EBU digital input and output for mono dual mono stereo or joint stereo audio Is an integrated multichannel asynchronous data multiplexer demultiplexer that can transmit and receive composite user data at rates of up to 9600 bps a Allows remote control from a desktop computer portable terminal or terminal emulator using either an RS 232 or optional multidrop RS 485 connection a Has a data passthrough mode for direct user data transfer without the internal multiplexer overhead a Provides 16 individual TTL opto isolat
107. relay contact outputs The 16 TTL sensor inputs go to the unit controller for formatting into relay control messages In turn these messages are sent through the system s ancillary data channel to directly control an external control console or event sequencer connected to the relay output port of the receivers The sensor inputs operate at TTL logic levels internally pulled up to 5 V The inputs become active by providing a dry contact closure to the signal ground on the relay control port This section describes the steps to complete the initial AC power up of the DAC700 unit To power up the DAC700 1 Make sure the DAC700 is properly installed in the equipment rack and the system cables are properly connected to the unit Ensure that all cables are installed before connecting to an AC power source 2 Turn on power for the remote control terminal desktop computer or terminal emulator and wait for it to initialize Make sure the computer COM port provides RS 232 communication and is connected to the unit M amp C port Configure the port for 2400 baud 7 data bits 1 stop bit and odd parity 3 Turn on the unit by connecting the power cord to the AC power jack on the unit When the power up initialization cycle has been completed as a minimum the green power LED will be illuminated Other LEDs may also be illuminated depending on your system configuration Once the DAC700 has been powered up verify the unit connections f
108. remain unchanged Remote Monitor and Control Operation 4 21 RM ST Relay Message Interval Use this command to set or read the time interval in 100 ms increments between relay control message updates Syntax RM lt parameter gt RM Parameters Valid lt parameter gt value range is 0 off through 100 10 seconds The default is 1 100 ms Real Time Status Use this command to read real time faults Syntax ST lt parameter gt Parameters The faults are bit mapped registers with each bit and associated weight assigned to a particular fault condition The table below provides a description of each fault and its weight Fault Condition Weight Encoder PLL not locked 1 Decoder PLL not locked 2 Decoder not framed out of sync 4 Audio Overload Left Channel 16 Audio Overload Right Channel 32 Network or channel ID fault 64 4 22 Remote Monitor and Control Operation TD TE Transmit Channel Rate Use this command to set or read the transmit channel data rate operation for the decoder Syntax q TD lt parameter gt TD Parameters Valid lt parameters gt are as follows a 56000 a 64000 96000 112000 128000 default a 192000 a 256000 a 384000 Set Protection Mode Use this command to set or read the protection mode Syntax TE lt parameter gt TE Parameters Valid lt parameters gt are as follows a O Disabled a 1 Ena
109. ring gt is an 8 byte character string with each character position controlling the normal state of a relay Each character is separated by a comma The first character controls relay number 1 the second character controls relay number 2 etc through relay number 8 A 1 for an individual character indicates that the relay is normally closed and that the relay is activated by opening it A 0 for an individual character indicates that the relay is normally open and that the relay is activated by closing it The default is 0 0 0 0 0 0 0 0 Display Configuration Use this command to instruct the receiver to display its software version Syntax DC 4 10 Remote Monitor and Control Operation DD Decoder Ancillary Data Rate Use this command to set or read the decoder ancillary Aux data baud rate Syntax DD 2 Parameters DD lt baud gt lt parity gt lt data_bits gt lt stop_bits gt The valid lt parameter gt values are as follows lt baud gt lt parity gt lt data_bits gt lt stop_bits gt Defaults 300 1200 2400 3600 4800 7200 9600 19200 384000 O E N odd even none Tor 8 1 or 2 38400 N 8 1 This value is automatically set when the AG value for the encoder is modified Remote Monitor and Control Operation 4 11 DM Duplex Mode Use this command to set or read the mux demux operation to full duplex or simplex mode Syntax DM lt mode gt DM Parameters Va
110. riptions Status Fault Indicator Lights Table 6 2 provides a description of fault conditions Periodically check the current and accumulated fault codes using the FL or ST commands at the remote control computer Table 6 2 Fault Conditions Fault Condition Tx PLL Unlock The TxPLL unlock fault occurs when the PLL reference is out of phase exceeds the 25 Hz limit or is not present Rx PLL Unlock This fault occurs when the PLL reference is out of phase exceeds the 25 Hz limit or is not present Decoder Not Framed This fault occurs when the encoder output is abnormal intermittent or fails causing the decoder to lose frame synchronization Audio Overload Left This fault occurs when the input level exceeds 18 dBu Channel maximum causing input clipping distortion and noise Audio Overload Right This fault occurs when the input level exceeds 18 dBu Channel maximum causing compression distortion and noise Network Channel ID Fault This fault is generated when the decoder has not received a network channel ID for a period of 10 seconds This fault indicates that either the decoder is not functioning properly or the encoder is not transmitting network channel IDs NOTE Check the RM value to make sure the relay interval is not zero Two front panel indicators provide fault alarm information Overload and Fault lights LEDs Check the indicator lights periodically along with the accumulated or real time fa
111. ry Commands 5 5 Controller Packet Command Example 5 5 ComStream Packet Protocol Communications Modes 5 6 Special Packet Control Commands 5 7 ComStream Packet Protocol Specifications 5 7 Chapter6 Maintenance and Troubleshooting Overview 6 1 Maintenance 6 1 Cleaning the DAC700 6 1 Performance Monitoring and Maintenance Commands 6 2 Fault Condition Descriptions 6 4 Status Fault Indicator Lights 6 4 Overload Indicator 6 4 Fault Indicator 6 5 Power Indicator 6 5 Connectors and Cables 6 5 General Troubleshooting 6 6 Unit Troubleshooting 6 7 Appendix A Technical Specifications and Port Information Audio Performance A 1 Available Audio Rates and Bandwidths A 2 Diagnostics A 3 Rear Panel Ports A 3 Rear Panel Port Mapping A 3 Analog Input Port A 3 Analog Output Port A 3 AUX AES Port A 3 Broadcast Data Port A 4 User Data Port A 4 Passthrough Port A 4 Contents Appendix B Glossary Index Relay Control Port A 4 M amp C Port A 4 Front Panel LED Status A 5 Mechanical IDU A 5 Power A 5 Environmental A 5 Interface Pinouts Analog Output Port J1 B 1 Analog Input Port J2 B 2 AUX AES Port J3 B 3 Broadcast Data Port J4 B 4 User Data Port J5 B 5 M amp C Port J6 B 6 Relay Control Port J7 B 7 vi Contents Figures Figure 1 1 Figure 1 2 Figure 1 3 Figure 2 1 Figure 2 2 Figure 2 3 Figure 2 4 Figure 2 5 Figure 2 6 Figure 2 7 Figure 2 8 Figure 2 9 Figure 2 10 Figure 2 11 Figure 2 12 Figure 2 13 Figure 2 14
112. s Users can preset definitions to match the configuration of the redundant DAC to one or more primary units Users can also configure the system to automatically swap DAC700s if a primary unit goes out of operation One of three types of ancillary data that can be processed by the DAC700 Relay blocks include the input relay information and the network ID and channel ID information Relay blocks are sent out at user programmable intervals in multiples of 100 ms The length of the interval is programmed in the DAC700 with the RM command Of the three types of data relay blocks have the highest priority Radio Frequency 4 Glossary RF Terminal RMA Rx Sampling Sampling Rate Shadow Simplex SR Subsystem Swap TDM TTCLK TTL Logic Levels Tx TxCLK UART UL Unprotected UPS A radio frequency terminal is composed of a modem an earth station a radio and an uplink dish Return Material Authorization Receive The process of converting continuous signals analog such as voice or music into discrete binary values The number of times per second that an analog signal is measured and converted to a binary number To act as a backup unit for example to provide an extra DAC700 to back up one or more other DAC700s See redundancy protection In simplex mode the DAC700 encodes and sends the digitally compressed data out without looping this information back through its onboard decoder Status Relay
113. smission of a digital master from one archive to another or from a remote site to a production studio It is assumed that the original copy is in a 16 bit linear PCM format and is to be compressed transmitted decompressed and stored in a 16 bit linear PCM format at the distant end Because the audio will endure future compression decompression cycles any contribution grade compression system must be able to withstand many encode decode cycles and postproduction without any apparent degradation Distribution grade systems are used to transmit audio between two storage devices or from a central production center to individual stations or transmitters However the number of subsequent encode decode cycles is limited to only a few Distribution grade systems are used when the number of audio compression decompression cycles are limited Emission grade systems are used when only one compression expansion cycle such as broadcast to the general public is anticipated This is the case when audio is compressed and transmitted from one place to another decompressed and stored on an analog tape and the only future manipulations done are in the analog domain Commentary grade systems are used for transmitting voice grade audio These definitions make no mention of the analog bandwidth or the exact definition They are vague terms used to describe ability of the audio to withstand multiple encode decode cycles In all cases the compressed audio is a
114. ssociated parameter is outside the expected range ER3 Indicates that the command is currently not available for example a function is not operating that would provide the expected results Command Summary Table 4 2 displays the DAC700 commands in a summary form Further details are provided in the next section Table 4 2 DAC700 Command Summary Command AB AG AM AS AT BL CF Cl CM CO CQ CS DC DD DM FL IN LB LR Description Analog bandwidth Aggregate encoder decoder ancillary data rate Alarm mask for status relay activation Algorithm select Audio test tone mode Block length Clear fault accumulation Channel ID sets for relay control messages Contact map definition for local relay closures Relay contact control for local relay closures Contact status query for local relay closures Contact sense for local relay closures Display configuration Decoder ancillary data rate selects Duplex mode Fault status accumulated Master reset reinitializes unit to default values Loopback mode selection Left right channel toggle AT LR and MU affect only DAC700 decoder audio function 4 2 Remote Monitor and Control Operation Table 4 2 DAC700 Command Summary continued Command MU NI PC PD PM PP PS PT RA RC RD RE RM ST TD TE TM TT UA UB UC UT XM Description Audio mute Network ID sets for relay control messages RS 232 mo
115. ssumed to be indistinguishable from the original ISO MPEG Layer II II A Functional Description 2 1 3 Quality vs bit rate The ISO MPEG Layer IIIA design allows the digital bit rate analog bandwidth and quality to be generally related by the following formula Digital Bit Rate Quality Digital Bit Rate Analog Bandwidth According to this formula the quality increases as the bit rate increases and the analog bandwidth is kept constant Similarly if the digital bit rate is kept constant and the analog bandwidth is decreased then quality improves The ISO tests in Stockholm in May 1992 have demonstrated that at a digital bit rate of 256 kbps per stereo channel ISO MPEG Layer II IIA is statistically identical to the original signal This means that the panel of approximately 60 highly trained listeners could not distinguish the original uncompressed source material from the audio compressed by the ISO MPEG Layer II IIA algorithm The conclusion of the ISO tests at 256 kbps per stereo channel was that ISO MPEG Layer II IA is transparent ISO MPEG Layer IIIA scored 5 on the Mean Opinion Score MOS scale where the lowest is 1 and the highest is 5 The qualities the ISO MPEG Layer IIIA algorithm provides at various bit rates is shown in Table 2 1 1 Table 2 1 1 Quality Grades and Bit Rates Quality Bit Rate Contribution 384 kbps stereo Layer II Distribution 256 kbps stereo Layer II Emission 192 kbps stereo Layer
116. t protocol uses the RS 485 bus interface to control devices that reside on the bus The RS 485 interface allows for a maximum of 31 devices to be connected to a single bus and is configured as a party line Each device on the bus is given an address from 1 to 31 and responds to commands and messages containing its specific address The default address for the DAC700 is 31 Packet Protocol Messaging Commands and messages are sent between a controller and individually addressable devices referred to as slaves via information packets Some packets sent from the controller may request a return acknowledgment packet from the slave This acknowledgment packet a Indicates if the command has been executed a Replies with the appropriate error and or status messages a Signals that the slave can receive and process another packet ComStream Packet Protocol 5 1 The rate at which the controller can send messages to a One specific slave is determined either a Implicitly by the slave s message handling rate specification a Explicitly by acknowledgment packets sent from the slave back to the controller a Different slaves are determined by the baud rate of the communication channel Packet Format and Content ComStream packet protocol runs under the standard asynchronous ASCII format with 1 start bit 7 data bits odd parity and 1 stop bit Each packet must conform to the format shown in Figure 5 1 Byte Device Control TX D S Count Ad
117. to select or read the algorithm to either ISO MPEG or Musicam Syntax AS lt parameter gt AS Parameters Valid lt parameter gt values are as follows a O default ISO MPEG Layer IIIA provides connectivity to proprietary codecs a 1 ISO MPEG Layer IIIA connectivity Audio Test Tone Mode Use this command to set or read the decoder tone generation mode Syntax AT lt parameter gt AT Parameters lt parameter gt specifies the channel s over which the tone is generated and the tone frequency A lt parameter gt of 1 to 6 generates a tone continuously until the user stops it by entering AT 0 Valid lt parameter gt values are as follows a O0 Normal operation default a Left audio channel 1 000 Hz tone a 2 Right audio channel 1 000 Hz tone a 3 Both audio channels 1 000 Hz tone a 5 Left audio channel 9 600 Hz tone a 6 Right audio channel 9 600 Hz tone a 7 Both audio channels 9 600 Hz tone Remote Monitor and Control Operation BL CF Cl Block Length Use this command to set or read the maximum block length used for the protocol of the ancillary data where lt parameter gt is the length of the block in bytes Syntax BL lt parameter gt BL Parameters Valid lt parameter gt values are from 30 to 255 The default is 30 ABR200 75 receivers can only accept block lengths of up to 50 bytes Clear Fault Use this command to clear the fau
118. uch as alcohol or benzene Use only a clean soft cloth lightly moistened with a mild detergent solution Wipe all equipment with a clean soft cloth lightly moistened with water to remove the detergent solution Maintenance and Troubleshooting 6 1 Performance Monitoring and Maintenance Commands The DAC700 has a number of commands for monitoring key system parameters and performing maintenance tasks By interrogating maintenance parameters on a periodic basis the overall system performance level can be determined and changed if necessary Table 6 1 describes the key performance monitoring and maintenance commands For more detail on these commands refer to the chapter on remote monitor and control operation These commands are implemented using a remote control terminal or desktop computer operating in terminal emulation mode For more detail on connecting the computer to the DAC700 see the chapter on installation and initial setup Table 6 1 Key Performance Montoring and Maintenance Commands Command Function AT Audio Test Tone CO Relay Contact Control DC Unit Configuration IN 9346 Master Reset Description This command sets the tone generation mode The DAC700 provides two internally generated audio test tones for checking the audio performance By entering the appropriate parameter the user can select an audio test tone and specify the channel to be checked the left channel the right channel or both The
119. ult codes on the remote control computer Overload Indicator The red overload warning indicator illuminates when the analog audio input level exceeds the 14 dBu limit The right channel analog audio is provided via the analog input port Maintenance and Troubleshooting Connectors and Cables Fault Indicator A red indicator light appears when a summary fault occurs This indicates one or more of the following failures a Audio muted or not present a Transmit or receive PLL out of lock a Encoder or decoder DSP errors a Unit controller watchdog time out exceeded a Processor memory failure Power Indicator The indicator light is green as long as AC line power is applied to the unit power supply and the internal DC voltages are normal The light goes off if one of the following fails a AC line power a Internal DC voltages a Power supply module Unreliable operating power can affect operation of the DAC700 unit and can sometimes damage electronic equipment or components Power disturbances can be caused by a variety of sources including lightning switching high power electrical equipment on and off and utility company activities such as power factor correction Power problems may cause slow or erratic unit operation audio distortion intermittent alarms or loss of configuration In some cases even unit or component failure can occur Check the connectors on the rear panel of the DAC700 unit for any of the follo
120. uts Pin 1 0 Name Description 1 AUXRTS Aux Request to Send 2 O RD Receive Data 3 TD Transmit Data 4 O CTS Clear to Send 5 O SG Signal Ground 6 RTS Request to Send 7 O AUXRD Aux Receive Data 8 AUXTD Aux Transmit Data 9 O AUXCTS Aux Clear to Send Interface Pinouts B 5 M amp C Port J6 The pin positions for the M amp C port connector are given in Figure B 6 OOOO O OO F087 Figure B 6 DB 9 Female RS 232 or RS 485 Connector The pinout specifications for the M amp C port connector are given in Table B 6 Table B 6 DB 9 Female RS 232 or RS 485 Connector Pinouts Pin 1 0 Name Description 1 TD Transmit Data RS 485 2 O RD Receive Data RS 232 3 TD Transmit Data RS 232 4 O CTS Clear to Send RS 232 5 O SG Signal Ground 6 RTS Request to Sent RS 232 7 TD Transmit Data RS 485 8 RD Receive Data RS 485 9 O RD Receive Data RS 485 B 6 Interface Pinouts Relay Control Port J7 The pin positions for the relay control port connector are given in Figure B 7 OOOOOUOOOOOOOOOOOOO QOOOOOOOOOOOOOOOOQOO Figure B 7 DB 37 Female Connector The pinout specifications for the relay control port connector are given in Table B 7 Table B 7 DB 37 Female Connector Pinouts o o N O oO A WO P it ct em Cs Cs Ce Co Oa nN O oa A O D O D _ D D D O O O O O O O M ao Pin 1 0 Name S1 S2 S3 S4 S5 S6 S7 S8 S9 S10 S11
121. ve timing signals for the audio input and output interfaces are provided by the clock generator module described later in this chapter Broadcast Data Interface The broadcast data interface consists of a full duplex synchronous RS 422 port The transmit and receive data channels operate independently at rates from 56 to 384 kbps The broadcast data port connects directly to the CM701 modem or equivalent for satellite transmission The transmit and receive data rates are selectable via the M amp C port 2 10 Functional Description and Theory of Operation Data Interfaces The data interface consists of two asynchronous RS 232 serial channels Each serial channel operates independently The audio data stream goes to the DAC Data channel 1 Data channel 1 is for user data The DAC700 processes formats and transfers user data following the ComStream proprietary protocol The maximum user data rate depends on the system s data transfer specifications User data rates are from 300 to 9600 bps Since user data has the highest priority in the encoding process at lower transmission rates 64 K 96 K and 112 K the higher the user data rate the more bits will be taken away from the audio content On the transmit side user data is input to the unit controller divided into blocks and transferred in packet format to the data multiplexer DSP 3 along with relay control blocks and network control blocks It multiplexes the anc
122. vel Restore input audio to normal peak level This indicates analog audio input to the right channel exceeds the 18 dBu maximum level Restore input audio to normal peak level This code indicates that audio digital encoder DSP 1 DSP 2 is not working correctly or has failed Anomalous or failed ADC operation affects downstream DSPs Check analog audio input a fitis overloaded too low or absent restore it to normal peak level Ensure audio digital decoder DSP 4 operation is normal Ensure DAC operation is normal Maintenance and Troubleshooting 6 7 COMSTREAM A Spar Company 6 8 Maintenance and Troubleshooting Audio Performance Technical Specifications and Port Information Operation Compression Technique Operating Rates Analog Operating Rates AES EBU Operating Modes Frequency Response Analog Sampling Rate Analog Input Levels Input Impedance Output Levels Digital 1 0 Total Harmonic Distortion Dynamic Range Signal to Noise Idle Channel Noise Crosstalk two channel Stereo Phase Deviation End End Gain End End Stability Channel Mute Full duplex encoder operates independently of decoder ISO MPEG Layer II IIA 56 64 96 112 128 192 256 and 384 kbps 64 96 128 192 256 and 384 kbps Mono dual mono stereo and joint stereo 15 Hz to 20 0 kHz 48 kHz 0 dBu average program level APL recommended 18 dBu max gt 100 kohm 18 dBu max active balanced
123. wing defects a Loose bent or broken pins or recessed or missing pins in a connector resulting in misalignment improper mating overheating intermittent electrical contact or shorting a Cracked or broken connector shells resulting in intermittent electrical contact or shorting a Bare wire contact with a metal casing resulting in overheating intermittent electrical contact or shorting a Defective threads missing guide pins or key misalignment resulting in improper mating electrical contact or shorting Maintenance and Troubleshooting 6 5 General Troubleshooting Check the interconnection cables on the unit and associated equipment for any of the following defects a Loose cracked or missing insulation and connectors on cables resulting in intermittent or no electrical contact or shorting Discolored melted or burnt insulation resulting from overloads exceeding voltage current ratings or shorting Cable routed too close to electromagnetic interference EMI sources resulting in intermittent data losses excessive signal noise crosstalk feedback or poor quality audio or data transmissions The general troubleshooting procedure requires using a remote control computer or laptop terminal Also the status and fault indicators on the front panel should be used to determine the cause of unit failures Associated system equipment or facilities fault indications should be used since they can assist in troublesh
124. xer installation site If an unterminated power cord is supplied with the unit the appropriate certified termination plug must be installed The following is a list of the required certifying agencies for various countries Country Agency Australia SAA Austria OVE Belgium CEBEC Canada CSA Denmark DEMKO Finland FEI France UTE Germany VDE India ISI Ireland IIRS Italy IMQ Japan MITI Netherlands KEMA New Zealand SECV SECQ SECWA EANSW ETSA HECT SANZ Norway NEMKO Rep S Africa SABS Spain AEE Sweden SEMKO Switzerland SEV UK ASTA BSI Route Power Cords Safely Route power cords so they are not walked on or pinched Pay particular attention to cords and connections at the plugs receptacles such as power strips and the point where they exit from the DAC700 Codec Multiplexer and attach to other equipment Do not place any items on or against power cords No Stacking Do not place or stack any objects on top of the DAC700 Codec Multiplexer Other equipment may be placed in a rack or on a shelf above or below the DAC700 Codec Multiplexer but never stacked directly on top of the modem itself Protect Against Lightning and Power Surges When the satellite communication equipment is installed have the professional installer ground the system to protect against voltage surges and built up static charges Protect the DAC700 Codec Multiplexer from lightning and powerline surges during a storm by unplugging it from the w

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