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Comtech EF Data CDM-625 Advanced Satellite Modem

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  • DoubleTalk Carrier-in-Carrier
  • 70/140 MHz and L-Band capabilities
  • Data Rates to 25 Mbps
  • Extensive backwards compatibility


SKU: SATRES-3472

System Specifications
Data Rate18 kbps to 25 Mbps, in 1 bps steps (Modulation, FEC & Data Interface dependant)
Symbol Rate18 ksps to 12.5 Msps
Operating Frequency50 – 180 MHz (Standard) AND 950 – 1950 MHz (Option), 100 Hz Resolution, Independent TX and RX operation
Major Operating ModesOpen Network, per IESS-308 / 309 / 310 / 314

Transparent, Closed Network per IESS-315

LDPC / TPC Codec (Optional Plug-in Module)

EDMAC Framed with/without AUPC

RS Outer Codec

High Rate ESC / Enhanced ESC (ESC++)

Drop & Insert (D&I) /Enhanced D&I++

Quad E1 Drop & Insert (QDI)

DoubleTalk Carrier-in-Carrier
FEC Options
NoneUncoded BPSK/QPSK/OQPSK
Viterbi: k=7, per IESS-308/309Rate 1/2 BPS/QPSK/OQPSK

Rate 3/4 QPSK/OQPSK

Rate 7/8 QPSK/OQPSK
Viterbi with Reed SolomonRate 3/4 16-QAM

Rate 7/8 16-QAM
Reed SolomonOpen Network and Closed Network modes
TCM (Per IESS-310)8-PSK/TCM Rate 2/3
Integrated LDPC and TPC

(2nd Gen) Codec

(Optional Plug-in Module)
LDPC Code Rates

Rate 1/2 BPSK/QPSK/OQPSK

Rate 2/3 QPSK/OQPSK/8-PSK/8-QAM

Rate 3/4 QPSK/OQPSK/8-PSK/8-QAM/16-QAM

TPC Code Rates

Rate 5/16 BPSK

Rate 21/44 BPSK/QPSK/OQPSK

Rate 3/4 QPSK/OQPSK/8-PSK/8-QAM/16-QAM

Rate 7/8 QPSK/OQPSK/8-PSK/8-QAM/16-QAM

Rate 0.95 QPSK/OQPSK/8-PSK/8-QAM
ScramblingIDR Mode, no RS, - per ITU V.35 (Intelsat variant)

IBS mode, no RS - per IESS-309, externally frame synchronized

Transparent Closed Network mode, no RS or TPC/LDPC - per ITU V.35 (Intelsat variant)

EDMAC mode, no RS coding - externally frame synchronized (proprietary)

TPC/LDPC modes - externally frame synchronized (proprietary)

All RS modes - externally frame synchronized per IESS-308/309/310
Management10/100 BaseT Ethernet with SNMP, HTTP and Telnet support, EIA-232, EIA-485 (2- or 4-wire)
Form C RelaysHardware fault, Rx and Tx Traffic Alarms, Open Network Backward Alarms
External Reference

(Input OR Output)
BNC Connector

Input: 1, 2, 5, or 10 MHz, -6 dBm to +10 dBm, 50Ω/75Ω (nominal)

Output: 10 MHz, 2.7 V peak-to-peak ± 0.4 V, Low Impedance Output
Modulator
Frequency Stability±0.06 ppm (±6 x 10-8), 0° to 50°C (32° to 122° F) with Internal Reference
Transmit FilteringPer IESS-308
Harmonics and SpuriousBetter than -60 dBc/4 kHz (typically <-65 dBc/4kHz)

Measured from 1 to 500 MHz (50-180 MHz band)

Measured F0 ± 500 MHz (950-1950 MHz band)
Transmit On/Off Ratio-60 dBc minimum
Output Phase Noise< 0.480° rms double sided, 100 Hz to 1MHz

(Minimum 16 dB better overall than the INTELSAT IESS-308/309 requirements)

dB/HzFrequency Offset
-63.0100 Hz
-73.01 kHz
-83.010 kHz
-93.0100 kHz
Fundamental AC line spurious is -42 dBc or lower

The sum of all other single sideband spurious, from 0 to 0.75 x symbol rate, is -48 dBc or lower
Output Power50-180 MHz: 0 to -25 dBm, 0.1 dB steps

(0 to -20 dBm in CDM-600 emulation mode)

950-1950 MHz: 0 to -40 dBm, 0.1 dB steps

(0 to -45 dBm in CDM-600L emulation mode, but power accuracy and spurious only guaranteed to -40 dBm)
Power Accuracy50-180 MHz:

±0.5 dB over frequency, data rate, modulation type and temperature range of 15 to 35° C

±0.8 dB over frequency, data rate, modulation type and temperature range of 0 to 50° C

950-1950 MHz:

±0.7 dB over frequency, data rate, modulation type and temperature range of 15 to 35° C

±1.0 dB over frequency, data rate, modulation type and temperature range of 0 to 50° C
Output Impedance

& Return Loss
50-180 MHz: 50Ω/75Ω, 16 db minimum return loss (18 dB typical), BNC Connector

950-1950 MHz: 50Ω, 19 db minimum return loss (21 dB typical), Type-N Connector
Clocking OptionsInternal, ±0.06 ppm (SCT)

External, locking over a ±100 ppm range (TT)

Loop timing (Rx satellite clock) - supports asymmetric operation

External Clock
External Tx Carrier OffBy TTL 'low' signal or external contact closure
BUC Reference (10 MHzVia TX IF center conductor, 10.0 MHz ± 0.06 ppm (With internal reference), selectable ON/OFF, 0.0 dBm ± 3 dB
BUC Power Supply

(HW Option)
24VDC, 4.17 Amps max., 90 W @ 50° C

48VDC, 3.125 Amps max., 150W @ 50° C (180 W @ 30° C)

Supplied through Tx IF center conductor and selectable ON/OFF via M&C control.
Demodulator
Input Power Range,

Desired Carrier
50-180 MHz: -105 + 10 log (symbol rate) to -70 + 10 log (symbol rate) dBm

950-1950 MHz: -130 + 10 log (symbol rate) to -80 + 10 log (symbol rate) dBm
Max Composite

Operating Level
50-180 MHz:

94 - 10 log (symbol rate, desired carrier) dBc, +10 dBm max, with the additional requirement that within ±10 MHz of the desired carrier the composite power is ≤ +30 dBc

950-1950 MHz:

102 - 10 log (symbol rate, desired carrier) dBc, +10 dBm max, with the additional requirement that within ±10 MHz of the desired carrier the composite power is ≤ +30 dBc
Absolute Maximum+20 dBm
Adaptive Equalizer5-tap design, selectable ON/OFF
Acquisition RangeProgrammable in 1kHz increments

Below 32 ksymbols/sec: ±1 kHz to ± (Rs) kHz, where Rs = symbol rate in ksymbols/sec

Between 32 and 389 ksymbols/sec: ±1 kHz to ±32 kHz Above 389 ksymbols/sec: ±1 kHz to ± (0.1 * Rs) kHz, up to a maximum of ± 200 kHz
Acquisition TimeHighly dependent on data rate, FEC rate, and demodulator acquisition range. E.g.: 120 ms average at 64 kbps, R1/2 QPSK, ±10 kHz acquisition sweep range, 6 dB Eb/No
Plesiochronous/

Doppler Buffer
Selectable from 64 to 262,144 bits, in 16-bit steps (Additional limitations for G.704 frame boundaries)
Receive ClockRx Satellite, Tx Terrestrial, External Reference
Clock Tracking± 100 ppm minimum
LNB Reference (10 MHz)Via RX IF center conductor, 10.0 MHz ± 0.06 ppm (With internal reference), selectable ON/OFF, -3.0 dBm ± 3 dB
LNB VoltageSelectable ON/OFF, 13 VDC, 18 VDC per DiSEq 4.2 and 24 VDC at 500 mA maximum
Monitor FunctionsEb/N0 estimate, Corrected BER, Frequency offset, Buffer fill state, Receive signal level
Doubletalk Carrier-In-Carrier
Delay Range0 to 330 ms
Power Spectral

Density Ratio
–7 dB to +11 dB (Interferer to Desired)
Eb/N0 Degradation0 dB Power Spectral Density Ratio

BPSK/QPSK/OQPSK: 0.3 dB

8-QAM: 0.4 dB

8-PSK: 0.5 dB

16-QAM: 0.6 dB

+10 dB Power Spectral Density Ratio

Additional 0.3 dB
Satellite RestrictionsSatellite in “loop-back” mode (i.e., the Transmit Station can receive itself)

“Non-processing” satellite (i.e., does not demodulate/remodulate the signal)
Environmental And Physical
TemperatureOperating: 0 to 50ºC (32 to 122°F)

Storage: -25 to 85ºC (-13 to 185ºF)
Power Supply100 - 240 VAC, +6%/-10%, 50/60 Hz, Auto sensing

-48 VDC (HW Option)
Power Consumption48 watts (typical with TPC/LDPC Codec and Carrier-in-Carrier module installed), 55 watts (max.)

280 watts (typical with TPC/LDPC Codec, Carrier-in-Carrier module and 48 VDC BUC power supply installed), 300 watts (max.)
Physical Dimensions (1RU)1.75H x 19.0W x 17.65D inches

(4.4H x 48W x 44.8D cm) approximate
Weight10.5 lbs (4.8 kgs) maximum, with all option modules and 48 VDC BUC power supply installed
See Datasheet for more specifications and Options

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