Theory Of Operation - Comtech EF Data SDM-9000 Installation And Operation Manual

SDM-9000 Satellite Modem

5.5.3 Theory of Operation

The Interface PCB consists of the following basic subsections:
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Refer to Figure 5-6 for the interface block diagram.
Rev.4
TX terrestrial receivers (data and clock)
RX terrestrial drivers (data and clock)
TX overhead MUX (ESC optional)
TX overhead receivers and processor
RX overhead DEMUX (ESC optional)
RX overhead processor and drivers
Baseband loopback relays
Interface loopback MUX
Plesiochronous buffer (optional)
Buffer clock MUX
Modem fault/alarm relays
Modem fault TTL outputs
Backward alarms (ESC optional)
Local monitor and control processor
Theory of Operation
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