The CDM-570A and the CDM-570AL are Comtech's next generation satellite modems that provide industry-leading performance and flexibility in a 1 RU package at a very competitive price. With support for VersaFEC® low latency LDPC Forward Error Correction (FEC), the revolutionary DoubleTalk® Carrier-in-Carrier® bandwidth compression, and optimized transmit filter rolloffs, the CDM-570A and CDM-570AL provide significant savings under all conditions. This combination of advanced technologies enables multi-dimensional optimization, allowing satellite communications users to:
The modems are available with 70/140 MHz or L-Band IF and EIA-530/-422, V.35, sync EIA-232 and G.703 T1/E1 data interfaces.
DoubleTalk Carrier-in-Carrier, based on patented “Adaptive Cancellation” technology, allows transmit and receive carriers of a duplex link to share the same transponder bandwidth. DoubleTalk Carrier-in-Carrier is complementary to all advances in modem technology, including advanced FEC and modulation techniques. As these technologies approach theoretical limits of power and bandwidth efficiencies, DoubleTalk Carrier-in-Carrier utilizing advanced signal processing techniques provides a new dimension in bandwidth efficiency. Figure 1 shows the typical full-duplex satellite link, where the two carriers are adjacent to each other. Figure 2 shows the typical DoubleTalk Carrier-in-Carrier operation, where the two carriers are overlapping, thus sharing the same spectrum.
When observed on a spectrum analyzer, only the Composite is visible. Carrier 1 and Carrier 2 are shown in Figure 2 for reference only.
As DoubleTalk Carrier-in-Carrier allows equivalent spectral efficiency using a lower order modulation and/or code rate, it can reduce the power required to close the link thereby reducing CAPEX by allowing a smaller BUC/amplifier and/or antenna. Alternatively, DoubleTalk Carrier-in-Carrier can be used to achieve very high spectral efficiencies E.g., DoubleTalk Carrier-in-Carrier when used with 16-QAM approaches the bandwidth efficiency of 256-QAM.
When combined with VersaFEC or TPC and optimized transmit filter rolloffs, DoubleTalk Carrier-in-Carrier provides unprecedented savings in transponder bandwidth and power utilization. This allows for its successful deployment in bandwidth-limited and power-limited scenarios, as well as reduction in earth station BUC/amplifier power requirements.
The patent-pending Carrier-in-Carrier Automatic Power Control (CnC-APC) mechanism enables modems on both sides of a CnC link to automatically measure and compensate for rain fade while maintaining the Total Composite Power. In addition to automatically compensating for rain fade, CnC-APC also enables the modems to share link margin, i.e. a modem can effectively transfer excess link margin to a distant end modem experiencing fade, thereby further enhancing overall availability.
VersaFEC is a patent-pending system of high-performance LDPC codes designed to provide maximum coding gain while minimizing latency. CDM-570A/L support Constant Coding & Modulation (CCM) mode of operation.
The Ultra Low Latency (ULL) codes provide even lower latency compared to standard VersaFEC codes.
CDM-570A/L support 5%, 10%, 15%, 20%, 25% and 35% transmit filter rolloff allowing users to further optimize the link. Carrier-in-Carrier
(contd.)
combined with VersaFEC and optimized transmit filter rolloffs can provide 50% or more BW savings compared to legacy modems.
The CDM-570A/L-IP has the ability to monitor and control the distant end of a point-to-point satellite link using EDMAC or EDMAC2. User data is framed and bits are added to pass control, status, and AUPC information. This is transparent to the user.
The modems support SNMP, web-based and command line interfaces for management. The modems can also be configured and monitored from the front panel, or through the remote M&C port. Ten complete RF configurations may be stored in the modem. An event log stores alarm and status information in non-volatile RAM, while the link statistics log stores link performance (Eb/No and AUPC performance) for monitoring and reporting purposes.
The FAST codes make it easy to upgrade the modem capability in the field. New features can be added on site, using FAST access codes purchased from Comtech EF Data that can be entered via the front panel.
Comtech EF Data CDM-570A Satellite Modem | |
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Data Rate Range | 2.4 kbps to 10.239 (depending on modulation, FEC and framing), 1 bps step with fully independent TX and RX rates |
Symbol Rate | 4.8 ksps to 3.0 Msps |
Frequency Range | CDM-570A: 50 to 90 or 100 to 180 MHz, 100 Hz resolution CDM-570AL: 950 to 2250 MHz, 100 Hz resolution |
Data Interfaces | EIA-422/-530 DCE, V.35 DCE, Sync EIA-232, G.703 T1 balanced, G.703 E1 balanced or unbalanced, 10 / 100BaseT Ethernet (option) |
Modulation & FEC Options | Data Rate Range |
VersaFEC-2 (Long Block) | |
BPSK 0.488 | 18.115 kbps to 1.468 Mbps (Minimum 37 ksps) |
QPSK 0.489, 0.537, 0.586, 0.611, 0.635, 0.660, 0.684, 0.733 | 36.230 kbps to 4.397 Mbps(Minimum 37 ksps) |
8-ARY 0.521, 0.537, 0.562, 0.586, 0.611, 0.635, 0.660, 0.684, 0.708, 0.733 | 125.081 kbps to 6.596 Mbps(Minimum 80 ksps) |
16-ARY 0.586, 0.611, 0.635, 0.660, 0.684, 0.708, 0.733, 0.757, 0.782 | 234.527 kbps to 9.381 Mbps(Minimum 100 ksps) |
32-ARY 0.660, 0.684, 0.708, 0.733, 0.757, 0.782, 0.801, 0.831, 0.855, 0.879 | 824.511 kbps to 10.239 Mbps(Minimum 250 ksps) |
VersaFEC-2 (Short Block) | |
BPSK 0.489 | 18.115kbps to 0.489Mbps(Minimum 37 ksps) |
QPSK 0.489, 0.537, 0.586, 0.611, 0.635, 0.660, 0.684, 0.733 | 36.230 kbps to 1.465Mbps(Minimum 37 ksps) |
8-ARY 0.521, 0.537, 0.562, 0.586, 0.611, 0.635, 0.660, 0.684, 0.708, 0.733 | 125.081 kbps to 2 Mbps(Minimum 80 ksps) |
16-ARY 0.586, 0.611, 0.635, 0.660, 0.684, 0.708, 0.733, 0.757, 0.782 | 234.527 kbps to 2 Mbps(Minimum 100 ksps) |
32-ARY 0.660, 0.684, 0.708, 0.733, 0.757, 0.782, 0.801, 0.831 | 824.511 kbps to 2 Mbps(Minimum 250 ksps) |
VersaFEC | |
BPSK 0.488 | 2.4 kbps to 1.462 Mbps |
QPSK 0.533 | 5.2 kbps to 3.200 Mbps |
QPSK 0.631 | 6.1 kbps to 3.785 Mbps |
QPSK 0.706 | 6.8 kbps to 4.233 Mbps |
QPSK 0.803 | 7.8 kbps to 4.818 Mbps |
8-QAM 0.576 (ECCM) | 8.3 kbps to 5.179 Mbps |
8-QAM 0.642 | 9.3 kbps to 5.782 Mbps |
8-QAM 0.711 | 10.3 kbps to 6.401 Mbps |
8-QAM 0.780 | 11.3 kbps to 7.021 Mbps |
16-QAM 0.644 (ECCM) | 12.4 kbps to 7.726 Mbps |
16-QAM 0.731 | 14.1 kbps to 8.776 Mbps |
16-QAM 0.780 | 15 .0 kbps 9.361 Mbps |
16-QAM 0.829 | 16.0 kbps to 9.946 Mbps |
16-QAM 0.853 | 16.4 kbps to 10.239 Mbps |
VersaFEC Ultra Low Latency (ULL) Codes | |
BPSK 0.493 (ULL) | 2.4 kbps to 1.479 Mbps |
QPSK 0.493 (ULL) | 4.8 kbps to 2.959 Mbps |
QPSK 0.654 (ULL) | 6.3 kbps to 3.923 Mbps |
QPSK 0.734 (ULL) | 7.0 kbps to 4.405 Mbps |
TPC | |
BPSK 5/16 | 2.4 kbps to 0.937 Mbps |
BPSK 21/44 | 2.4 kbps to 1.430 Mbps |
QPSK/OQPSK 21/44 | 4.8 kbps to 2.860 Mbps |
QPSK/OQPSK 3/4 | 7.2 kbps to 4.500 Mbps |
QPSK/OQPSK 7/8 | 8.4 kbps to 5.250 Mbps |
QPSK/OQPSK 0.95 | 9.1 kbps to 5.666 Mbps |
8PSK/8-QAM 3/4 | 10.8 kbps to 6.750 Mbps |
8PSK/8-QAM 7/8 | 13.6 kbps to 7.875 Mbps |
8PSK/8-QAM 0.95 | 15.3 kbps to 8.500 Mbps |
16-QAM 3/4 | 14.4 kbps to 9.000 Mbps |
16-QAM 7/8 | 16.8 kbps to 9.980 Mbps |
Viterbi | |
BPSK 1/2 | 2.4 kbps to 1.500 Mbps |
QPSK/OQPSK 1/2 | 4.8 kbps to 3.000 Mbps |
QPSK/OQPSK 3/4 | 7.2 kbps to 4.500 Mbps |
QPSK/OQPSK 7/8 | 8.4 kbps to 5.250 Mbps |
Viterbi + Reed Solomon | |
BPSK 1/2 | 2.4 kbps to 1.363 Mbps |
QPSK/OQPSK 1/2 | 4.3 kbps to 2.727 Mbps |
QPSK/OQPSK 3/4 | 6.5 kbps to 4.090 Mbps |
QPSK/OQPSK 7/8 | 7.5 kbps to 4.666 Mbps |
16-QAM 3/4 | 13.0 kbps to 4.000 Mbps |
16-QAM 7/8 | 16.8 kbps to 4.666 Mbps |
TCM + Reed Solomon | |
2/3 8PSK TCM (Closed network) | 8.7 kbps to 4.400 Mbps |
Uncoded | |
Uncoded BPSK | 4.8 kbps to 3.000 Mbps |
Uncoded QPSK/OQPSK | 9.6 kbps to 5.000 Mbps |
Scrambling | Mode dependent – ITU V.35, or proprietary externally synchronized |
M&C Interface | Ethernet 10/100Base-T, EIA-232, EIA-485 |
Input/Output Impedance | CDM-570A: matched for 50/75 Ω, 17 dB minimum return loss, BNC connector CDM-570AL: transmit and receive 50 Ω, > 17 dB (950 MHz to 2250 MHz) and >19 dB (1000 MHz to 1900 MHz) minimum return loss, female Type N connector |
External Reference Input | 1, 2, 5, or 10 MHz, BNC connector |
Form C Relays | TX, RX traffic alarms and unit faults |
Modulator | |
Frequency Stability (With Internal Reference) CDM-570A CDM-570AL | ±1 ppm, 0º to 50ºC (32º to 122ºF) ±0.06 ppm, 0º to 50ºC (32º to 122ºF) |
Output Power CDM-570A CDM-570AL | 0 to –25 dBm, 0.1 dB steps 0 to –40 dBm, 0.1 dB steps |
Accuracy CDM-570A CDM-570AL | ± 0.5 dB over frequency and temperature ± 1.0 dB over frequency and temperature |
Phase Noise CDM-570A CDM-570AL | < 0.75 degrees RMS double-sided, 100 Hz to 1 MHz < 1.2 degrees RMS double-sided, 100 Hz to 1 MHz |
Output Spectrum/ Filtering | Meets IESS-308/-309 power spectral mask |
Alpha (Rolloff) | 5%, 10%, 15%, 20%, 25% and 35% |
Harmonics and Spurious | -60 dBC/4 kHz from 600 to 2600 MHz (L-Band), from 1 to 400 MHz (IF) |
Transmit On/Off Ratio | 55 dB minimum |
External TX Carrier Off | By TTL LOW signal, or RTS |
TX Clock Options | Internal (SCT), external (TT), loop timing with symmetric or asymmetric operation (data interface dependent) |
Demodulator | |
Input Power Range CDM-570A CDM-570AL | -30 to -60 dBm -130 + 10 log symbol rate, dBm (minimum) -90 + 10 log symbol rate, dBm (maximum) |
Max Composite Level CDM-570A CDM-570AL | +35 dBc, up to -5 dBm absolute max. +40 dBc, up to -10 dBm absolute max. |
Acquisition Range CDM-570A CDM-570AL | ± 1 to ± 32 kHz,1 kHz step ± 1 to ± 32 kHz, 1 kHz step, symbol rate <= 625 ksps ± 1 to ± 200 kHz,1 kHz step, symbol rate > 625 ksps |
Acquisition Time | Highly dependent on data rate, FEC rate, and demodulator acquisition range. Example: 120 ms average at 64 kbps, Rate 1/2 QPSK, ± 10 kHz acquisition sweep range, 6dB Eb/No |
Plesiochronous/ Doppler Buffer | ±128, 256, 512, 1024, 2048, 4096, 8192, 16384 or 32768 bits |
Receive Clock Options | Buffer disabled (RX satellite), buffer enabled (symmetric or asymmetric operation) (data interface dependent) |
Clock Tracking | ± 100 ppm minimum |
Monitor Functions | Eb/No, frequency offset, BER, buffer fill status, RX signal level |
DoubleTalk Carrier-in-Carrier | |
Delay Range | 0 to 330 ms |
Power Spectral Density Ratio (Interferer to Desired) | -7 dB to +7 dB |
Maximum Symbol Rate Ratio | 3:1 (TX:RX or RX:TX) |
Eb/No Degradation | 0 dB Power Spectral Density Ratio BPSK/QPSK/OQPSK: 0.3 dB 8-QAM: 0.4 dB 8PSK: 0.5 dB 16-QAM: 0.6 dB +10 dB power spectral density ratio Additional 0.3 dB |
Satellite Restrictions | Satellite in “loop-back” mode (i.e., the transmit station can receive itself) “Non-processing” satellite (i.e., does not demodulate or remodulate the signal) |
Low-Noise Block Converter(LNB) Support | |
LNB Voltage | 13 and18 VDC |
LNB Reference | 10 MHz via RX center conductor |
Block Up Converter (BUC) Support | |
BUC Voltage | 24 VDC, 90 W @ 50°C, 100 W @ 30°C (internally fitted option) 48 VDC, 150 W @ 50°C, 180 W @ 30°C (internally fitted option, not available with -24 VDC input) |
BUC Reference | 10 MHz via TX center conductor |
FSK Support | Via TX center conductor with FSK BUCs |
Environmental & Physical | |
Temperature Operating Storage | 0 to 50°C (32 to 122°F) -25 to 85°C (-13 to 185°F) |
Power Supply | 100 to 240 VAC, 50/60 Hz -24 VDC (HW option) -48 VDC (HW option) |
Power Consumption | CDM-570A: 29 W typical (32 W max.) CDM-570AL: 29 W typical (32 W max.) w/o BUC |
Dimensions (height x width x depth) | CDM-570A: 1.75” x 19” x 13” (4.4 x 48.3 x 330 cm) CDM-570AL: 1.75” x 19” x 16” (4.4 x 48.3 x 40.6 cm) |
Weight | CDM-570A: 5 lbs (2.3 kg) CDM-570AL: 7 lbs (3.2 kg) (without BUC P/S) CDM-570AL: 16 lbs (7.2 kg) including 150 W BUC power supply |
Operations & Maintenance | |
Configuration and Management | Front panel Remote port – EIA-232 or EIA-485 (2- or 4-wire) SNMP with MIB II and private, modem-specific MIB Telnet Web browser (HTTP) |
Software/firmware upgrade via FTP | |
Faults and alarms | |
Configuration backup and restoral | |
Security | |
Password protection for web, ftp and telnet | |
Access list | |
Regulatory | |
CE Mark | EN 301 489-1 (ERM) EN55022 (Emissions) EN55024 (Immunity) EN 61000‐3‐2 EN 61000‐3‐3 EN60950 (Safety) |
FCC | FCC Part 15, Subpart B |