Comtech EF Data SDM-9000 - Manual (Page 203)

SDM-9000 Satellite Modem Options
Rev. 4 A–17
Parameters for TX baseband interface timing are presented in Table A-3.
Table A-3. Receive Baseband Interface Timing
Parameter Description Min Max
t
cko
Delay time, CLOCK to DATA or SYNC valid 5 ns
t
h
Hold time, CLOCK to DATA or SYNC invalid 2 ns
t
cl
CLOCK low time 8 ns
t
ch
CLOCK high time 8 ns
A.2.4.2.1 DBS Mode Receive SYNC Pulse Timing
In DBS mode, a one clock-period-wide sync pulse is supplied coincident with the first bit
of the sync byte (0x47). After the sync byte interval, 187 bytes (1,496 bits) of packet
data, followed by 16 bytes (128 bits) of zeros, are output from the modem. Refer to
Figure A-13.
Figure A-13. DBS Mode Receive SYNC Pulse Timing
Receive packets that could not be corrected by the Reed-Solomon decoder are indicated
with an extended sync pulse (two clock-periods-wide) as shown in Figure A-14.
Figure A-14. DBS Mode Receive with Extended SYNC