Comtech EF Data SDM-650B - Manual (Page 27)

SDM-650B Satellite Modem Introduction
Rev. 5 1–3
The modem contains:
• Built-in
scrambler/descrambler
• Differential
encoder/decoder
• Transmit and receive frequency synthesizers
• Multi-rate Forward Error Correction (FEC) convolutional encoder-sequential
decoder (Viterbi K=7 is optional)
The modem provides high performance with:
• Narrow occupied bandwidth
• Automatic signal acquisition
• High
flexibility
• Extensive online monitoring circuits
1.2 Description
The modem is a complete, self-contained unit in a standard 19” rack-mountable enclosure
weighing approximately 25 lbs.
The modem is of modular construction (Figure 1-3).
The chassis assembly (with the front and rear panel) encloses several Printed Circuit Boards
(PCBs). The backplane PCB is mounted on the chassis assembly, and contains receptacles
for five plug-in PCBs.