MCPC Digital Receiver With Store and Forward Capability


for Satellite Based Data, Audio and IP Multicast Broadcast Systems

Model DCR-974 DigiCeiver


The Model DCR-974 DigiCeiver® is a digitally implemented data receiver intended for use in satellite based broadcast systems. The Model DCR-974 utilizes newly available digital technology to allow a wide degree of flexibility to the user, without the necessity of hardware configuration changes. This enables the user to upgrade his system, after deployment, without hardware modifications. All operating parameters are programmable through the front panel operator interface, receiver remote control port or satellite network control (NCS) channel. The operating software may be downloaded via satellite to provide for future upgrades.

The Model DCR-974 Provides operation at digital symbol rates from 64 ksps to 4096 ksps. This provides data rates of 64 kilobits per second (kbps) up to 2048 kbps in the BPSK mode or 64 kbps up to 4096 kbps in the QPSK mode in increments of 64 kbps.

A choice of high performance forward error correction decoders (FEC) are available. A sequential decoder is available, and a Viterbi, rate 1/2, k=7 FEC decoder is also available. An additional option for a concatenated Reed-Solomon/Viterbi decoder will provide essentially error free operation at any Eb/No above "threshold".

The DCR-974 is fully compatible with existing BPSK and QPSK, 1/2 rate coded digital signals currently transmitted by many service providers.

The DCR-974 provides two serial data output ports. Each port can provide operation in an SCPC mode or may provide an output channel from either a packet multiplexed or TDM data stream. The electrical interface may be configured as either RS-232 or RS-422.

A 10/100 Base-T Ethernet port is also provided, which will output a high speed channel utilizing an IP protocol. This enables the transmission of high speed data, or files, to host servers at the receive site.

An important feature of the DCR-974 is its ability to store data within the receiver in a mass storage device. The receiver can optionally house up to two storage drives which can include one IDE hard disc drive of typical size 2 Gbytes, and one or two IDE Flash drives of typically 64 Mbytes. The drives can be used to store data files of any type. This can include textual information, web pages, audio files etc.

Option Cards

Additional data output channels may be provided by use of the DDP-104 four channel demultiplexer expansion card. The DDP-104 can provide demultiplexing of either TDM or packet multiplexed channels. Each output channel of the DDP-104 is capable of being operated in either a TDM (transparent) mode or in an HDLC (packet multiplexed) mode compatible with the ICP AD3311 packet multiplexer. Provision is made for the output electrical interface to be either RS-232 or RS-422. Using two DDP-104 cards, up to eight data output ports may be added to the basic DCR-974 receiver's two built in ports, for a total of 10 ports plus the Ethernet port.

The DAP-104 (4 channel) digital audio expansion board may also be installed. The DAP-104 (4 channel) card can decode two MPEG audio streams to provide four audio channels. Both analog audio outputs and AES/EBU digital outputs are available. Each expansion card also provides up to 8 remote contact closures. In addition, ancillary data streams may be provided from the MPEG decoders. Two expansion cards may be utilized to provide up to 8 audio outputs and 16 closures in a single receiver chassis.

The SAP-104 audio store and forward expansion board supports the simultaneous decoding of 4 MPEG audio streams, or up to 8 audio channels in the dual mono mode. In addition the SAP-104 provides for the playback, of real-time audio or audio files previously downloaded from the network head end and stored within the receiver. These pre-stored audio files are transported in the IP multicast channel over the satellite, and are stored in a mass storage device in the main receiver. The SAP-104 also supports up to 16 switch closure inputs to trigger preselected events and up to 16 switch closure outputs capable of triggering events in the affiliate station from the network head end.

The Model DCR-974 is packaged in a low profile 3" high table top mounted chassis. An internal, universal input, switching power supply provides operation from AC power anywhere in the world.

An optional 2U (3 2 in) high rack mounting adapter is also available.

DCR-974 Characteristics

Input Characteristics

Input Frequency Range

950-1450 MHz (compatible with "Data Grade" C-Band or Ku-Band low noise block down converters)

Input Impedance

75 Ohms

Input Connector

Type "F" female

Noise Figure

15 dB maximum

Maximum Input Power

-30 dBm (per transponder)

-20 dBm (950 MHz to 1450 MHz)

Minimum Signal Level

-85 dBm @ 64 kbps,

-70 dBm @ 2048 kbps

Carrier Frequency Tuning

Synthesized in 0.10 MHz steps from 950 MHz to 1450 MHz

Demodulator Characteristics

Symbol rate:

64 ksps to 4096 ksps depending on data rate, FEC encoding rate and modulation mode.

PSK mode

BPSK or QPSK, programmable Data rate:

64 kbps up to 2048 kbps in 64 kbps increments, in BPSK mode, or 128 kbps up to 4096 kbps in, 64 kbps increments, also 1544 kbps, in QPSK mode.

Matched filtering

40% rolloff square root Nyquist

Demodulator Architecture

Costas loop with digitally implemented carrier and clock recovery phase-locked loops.

Ambiguity Resolution

Differential decoding


V.35 (IESS 308)

Forward Error Correction (factory selectable).

Rate 1/2 sequential decoder, with 2 bits soft decisions, implemented in a custom ASIC. K=7, or

Rate 1/2 , 3 bit soft decision Viterbi decoder.

Option for concatenated Reed-Solomon/Viterbi FEC decoder compatible with DVB standard.

Data format:

Compatible with existing BPSK and QPSK rate 2 coded signals presently transmitted by many service providers.

Performance Characteristics

Frequency uncertainty sweep

Programmable up to +2 MHz

Demodulator Lock-up time

Approximately 2 seconds typical, 4 seconds maximum when configured for 384 kbps QPSK with 125 kHz frequency uncertainty. Lock-up time is less for higher data rates and for the BPSK mode.

Bit Error Rate Performance

Typically within 0.4 db of PSK theory in BPSK mode and within 0.6 db of theory in the QPSK mode.

Receive clock frequency uncertainty range

Greater than 10-4

Demultiplexer Characteristics

Aggregate Rate:

64 kbps up to 4096 kbps in an 64 kbps increments compatible with clear channel fractional T1/E1 services. The aggregate may be composed of a combination of TDM and HDLC (packet multiplexed) channels.

Channel Rates:

Increments of 64 kbps up to 2.048 Mbps in the TDM mode. Standard synchronous and asynchronous rates from 300 baud up to 115,200 baud in the ICP packet multiplexed mode.

TDM Channels:

In the TDM mode provides channels which are synchronous with the clock provided by the multiplexer on the transmit end and by the demultiplexer on the receive end. The TDM channels are transparent, or independent, of protocol. The TDM channels may be provided in increments of 64 kbps up to 2.048 Mbps.

Packet Multiplexed Channels:

Packet multiplexed synchronous or asynchronous channels may be provided by the ICP DCR-974 receiver. The packet multiplexed channels are transmitted within the TDM channels which are allocated to packet data within the aggregate stream. Standard baud rates are supported. The DCR-974 receiver supports the ICP packet multiplex protocol which is compatible with the ICP (and Scientific Atlanta) packet de-multiplexing protocol.

IP Multicast Channel:

An IP multicast channel may be included in the aggregate data stream. This channel transports IP packets from the headend to the receiver. This channel may be used to transport a high speed channel capable of transporting many types of data including text, audio or video files, etc. The output of this channel is available as a 10/100Base-T electrical interface.Audio Channels:

Audio Channels

TDM channels may be allocated to provide capacity for real-time MPEG Layer II digital audio channels providing high quality audio outputs up to 20 kHz in bandwidth. Audio decoding is provided via the DAP-104 plug-in expansion card.

The SAP-104 audio store and forward expansion card also provides for the decoding of up to 4 MPEG audio streams as well and storage and playback of real-time streaming audio and audio files.

Number of Output Channels:

The DCR-974 will output one, or two, data channels from the multiplexed aggregate. A 10/100Base-T Ethernet interface is also available. Additional output channels may be provided by the installation of DDP-104 expansion cards.

Electrical Interface:

Output channels are provided as an EIA RS-232 or RS-422 electrical interface. Selectable via plug-in interface IC's.

Demultiplexer Configuration:

The configuration of the demultiplexer is controlled at the receive site via the control channel which is multiplexed into the primary channel. Any multiplexed channel may be assigned to any physical output port.

Configuration Storage:

The configuration of the receiver and demultiplexer is retained in non-volatile memory on the PWBs.

Storage Characteristics

Storage media Optional 2.5" laptop IDE hard drive. Optional solid state IDE flash drive. Up to two storage drives can be accommodated.

Options available are:

1. No storage

2. IDE hard drive

3. IDE Flash drive

4. IDE hard drive and IDE flash drive

5. Two IDE flash drives.

Audio sources for storage IP Multicast stream or up to two real time TDM audio streams
Types of data that can be stored MPEG layer 2 audio files and Data files

Data Demultiplexer Expansion Cards

See separate specification for the DDP-104 digital demultiplexer expansion board.

Digital Audio Expansion Card

See separate specification for the DAP-104 digital audio expansion board.

Digital Audio Store and Forward Card

See separate specification for the SAP-104 store and forward expansion board.

Synchronization and Control Channel Characteristics

Channel Structure:

The synchronization and control channel consumes a total of 8 kbps. 4 kbps are used to transmit the synchronization pattern used to recover frame timing in the demultiplexer. The remaining 4 kbps are available for control of the associated satellite receiver. This remote control channel is an internal interface to the receiver and is not available externally.

Carrier Identification:

The 4 kbps synchronization channel also contains information that allows the receiver to identify the proper carrier in a multi-carrier system. Up to 254 carriers may be provided with unique identifiers. The proper identifier is user selectable via front panel or NCS.

Network Control Characteristics


Each site is individually addressable. Addresses may be global, group or individual.

Receiver address:

Each receiver contains a serial number which is unique and permanently assigned to the receiver at the time of manufacture. The serial number may be read at the remote site via the panel display or the remote NCS port.

NCS Commands:

The complete NCS command set is found in ICP Network Control System protocol specification.

Network Control Interface:

Commands may be generated by the head end NCS computer or accepted from external sources.

Panel Controls and Indicators

Controls (via control panel keypad)

LNB band, carrier frequency selection, BPSK/QPSK mode, data (symbol) rate, sweep width, local or remote control, signal strength (Eb/No) display, error rate display and other parameters depending on receiver configuration.


LEDs Indicate: Power, Summary fault, LNB Fault, Demodulator sync, Carrier ID recognition, Local mode, and download status

LCD alphanumeric display panel indicates: LNB Band, Carrier frequency, Signal Quality (Bit Error Rate), Carrier Frequency Sweep, Mode of operation (BPSK/QPSK), Signal strength (Eb/No), Software version, Serial number, and other messages


Input (LNB) connector

Type "F" female

Data output connectors

9 pin female Type "D" connector

Remote/ diagnostic connector

9 pin male Type "D" connector

Ethernet port

RJ-45 connector

Baseband port

RJ-45 connector

AC power

IEC 320 connector


AC input, LNB current

Remote/Diagnostic Port


Remote control of receiver configuration. Monitor of receiver operating parameters. All front panel functions may be accessed through this port. Connector pin-out compatible with RS-232 telephone modem.

Data and message protocol

Serial data communications. Protocol and message definition will be found in the ICP Network Control System protocol specification. Baud rate

Standard baud rates up to 38400 bps.


LNB Power

+20 V nominal at up to 0.5 A. separately fused and surge protected, supplied on the center conductor of the LNB cable. The LNB power is front panel controlled.

AC Power

Universal input, 90 VAC to 260 VAC, 47 Hz to 63 Hz, less than 50 watts



Table top mounting, option for rack mounting.


3" high, 12" wide, 12" deep metal chassis with molded plastic front panel.


Less than 7.5 lbs (3 Kg)

Environmental (Operating)


0 degrees C. to +50 degrees C. operating temperature.


0 to 100% non condensing.

Shock and Vibration

Unaffected by commercial shipping, handling and maintenance.

Click Here for View of DCR-974 Rear Panel With SAP-104 Audio Card Installed