Chapter 1. INTRODUCTION
1.1
Overview
The CDM-625 Advanced Satellite Modem, shown in
Figure 1-1
, is intended for both modern
closed network and legacy Intelsat applications. It is a highly-evolved replacement for the
CDM-600 and CDM-600L modems that includes many new features.
Figure 1-1. CDM-625 Advanced Satellite Modem
•
The CDM-625 offers variable data rates from 18 to 25 Mbps, in BPSK, QPSK, Offset
QPSK, 8-PSK, 8-QAM and 16-QAM modes. Viterbi, concatenated Reed-Solomon (RS),
Trellis Coded Modulation (TCM), Turbo Product Coding (TPC), and Low-density Parity
Check Coding (LDPC) are provided as Forward Error Correction (FEC) options.
•
It is compliant with IESS-308/309/310/315 specifications, but also adds significant other
features in closed network modes.
•
A new demod design incorporates fast acquisition, improved composite power handling,
and an integrated adapative equalizer.
•
A full range of traffic data interface types is built-in (no plug-in cards required) including
all G.703 types, Quad E1 Drop and Insert, HSSI, and ASI.
•
The IF frequency range simultaneously covers 50 - 180 MHz and 950 - 1950 MHz.
•
It can be equipped with a DoubleTalk
®
Carrier-in-Carrier
®
option card that can save up to
50% transponder bandwidth.
•
The modem is compact, 1RU high and 17.6 inches deep, and consumes only 48 watts
(typical).
•
It has a front panel Vacuum Fluorescent Display (VFD) and keypad for local configuration
and control, although it can be fully remote-controlled.
1–1
