SatModem From Comtech Packs In Advanced Comm Features

In high volume production is the CDM-625 Advanced Satellite Modem from Comtech EF Data Corporation. This is the first modem to combine the Low Density Parity Check (LDPC) Forward Error Correction (FEC) with the DoubleTalk™ Carrier-in-Carrier® bandwidth compression. Suited for mobile and telecom operators, sat service providers, government and military entities, as well as enterprise users, this unit is based on the patented “Adaptive Cancellation” technology. This allows the transmit and receive carriers of a duplex link to share the same transponder space. LDPC is an advanced FEC capable of providing performance much closer to the Shannon limit, as compared to other techniques. The combo of LDPC and DoubleTalk Carrier-in-Carrier can enable savings in transponder bandwidth and power use, as well as earth station BUC/HPA size.

The CDM-625 includes a number of other advanced features. Supporting 70/140 MHz and L-Band capability in the same unit with independently selectable transmit and receive IF, it simplifies sparing and stocking in networks requiring both frequencies. It features data rates from 18 kbps to 25 Mbps and symbol rates of 18 ksps to 12.5 Msps. The unit supports Viterbi, Concatenated Reed Solomon, and TCM Forward Error Correction plus an integrated TPC and LDPC codec. Providing ultimate flexibility for diverse environments, the CDM-625 offers a wide range of data interfaces, including EIA‑422/530, V.35, G.703 T1, G.703 E1, G.703 T2, G.703 E2, Quad G.703 E1, ASI, LVDS, HSSI, and 4-port 10/100BaseT Ethernet for traffic bridging. Additionally, the CDM-625 provides several options for local and remote management and is also backwards compatible with the CDM-600/L Satellite Modems. The satmodem even supports a CDM-600/L emulation mode that makes it easy to deploy in existing networks using CDM-600/L without changes to the 1:N redundancy switches or the management platform—Tempe, Arizona