Comtech EF Data SDM-2020 - Manual (Page 194)

SDM-2020 Satellite Demodulator Revision 4
ASI/LVDS Data Interface MN/SDM2020D.IOM
13–4
Table 13-1. ASI/LVDS Specifications (Continued)
LVDS Specifications
Data Rate
1.5 to 100 Mbps, parallel LVDS
Clock Rate Uncertainty Programmed data rate + 100 ppm
Connectors 25-Pin D female per EN 80053-9.
Same connector is either TX or RX data (See Loopback / Loop
Thru)
Electrical Properties per EN 80053-9
Signal Types D0 – D7, Sync, Dvalid and Clock per EN 80053-9
Data synchronization is detected by correlating the data stream
for the MPEG2 sync pattern per ETS 300 421.
Auxiliary Specifications
Fault Signal
MF (modulator fault) and DF (demodulator fault). OC-TTL fault
outputs.
TX ON / OFF TTL input, when enabled this signal turns the TX carrier ON /
OFF.
Ext Clock Pin(s) reserved, but not defined
Monitor & Control
Interface Select
ASI or LVDS
Auxiliary Functions Transmitter Control: TX IF Control ON / OFF
Polarity select Normal or Inverted
Controlled Functions Interface Select: ASI or LVDS
Interface Loopback
Interface Loop Thru
Data Rate
TX ASI Data Input J3 / J4 Select
Loss of data. Programmable as Fault or Alarm
Clock, Normal or Inverted
Data, Normal or Inverted
Monitored Functions Loss of TX Data (Data Connector Removed): The modulator
indicates a loss of sync (framed modes) and transmits all 1s in
the data portion of the frame.
The demodulator detects the presence of all ones and reports it
to the display and remote port.
TX clock PLL program error
Data violations (TX)
FIFO Faults
ASI Data Loop BW
Selection Wide and Narrow
Additional M&C
Monitored Functions
Loss of TX Data or Clock (Data Connector Removed): The
modulator indicates a loss of sync (frame and mode) and transmits
all 1s in the data portion of the frame.
The demodulator detects the presence of all ones and reports it to
the display and remote port.