Figure 3-9. G.703 2048 Interface Block Diagram - Comtech EF Data SDM-650B Installation And Operation Manual

SDM-650B Satellite Modem
TX CLOCK
M
TX DATA
O
RX CLOCK
D
E
RX DATA
M
COMMON EQUIPMENT
MODULATOR
DEMODULATOR
DATA BUS TO M & C
The G.703 2048 kbit/s interface will operate in AMI, enabled by SW1-8.
The data to be transmitted by the modem is input on the SD lines. Jitter on the SD is
removed by a FIFO and clock recovery phase-locked loop. Data received and
demodulated by the modem is output on the RD lines.
The G.703 2048 kbit/s interface provides bi-directional loopback of the data at the DCE
interface. In loopback from the DTE side, SD is connected to RD. From the modem side,
the received demodulated data is routed back to the modulator input for re-transmission.
Three fault outputs are provided on dry contact FORM C relays:
•
•
•
Rev. 5
TO BUFFER
OPTIONS
DS-1
DEJITTER
TO BUFFER
OPTIONS
FAULT
RELAYS
CONTROL
LOGIC

Figure 3-9. G.703 2048 Interface Block Diagram

Common Equipment
Modulator
Demodulator
N X 64 KB
CLOCK
SYNTHESIZER
DS-1 LINE
RECEIVER/
DRIVER
LOOPBACK CONTROL
EXTERNAL BUFFER CLOCK
TTL MODULATOR FAULT
TTL DEMODULATOR FAULT
Configuration
SD
T
RD
E
R
R
E
S
T
MC
R
I
A
L
3–25