Comtech EF Data SNM-1001L - Manual (Page 262)

SNM-1001L Satellite Modem Revision 1
Specifications MN/SNM1001L.IOM
A–24
A.10 Interface Specifications
A.10.1 TX Clock Switching Due to Failure of Selected Clock
The modem will automatically switch the TX clock source to SCT internal on failure of
terminal timing.
A.10.2 TX Clock Phase Adjustment
The operator can set the TX clock phase to Normal, Inverted, or Auto Mode.
A.10.3 TX Data Phase Adjustment
The operator can set the TX data phase to Normal or Inverted.
A.10.4 Transmit Clock Source
The transmit clock can be selected by the operator from the following sources.
Terrestrial. Must be
± 100 PPM of the programmed rate, ≤ 5% jitter.
SCT (internal). Same as selected frequency reference.
A.10.5 Send Clock Timing Source
The send clock timing output can be generated from the Frequency Reference (either via
the front panel or remotely). In this mode, the send clock timing will have the accuracy of
the selected internal or external reference.
1. If loop timing is selected, the send clock timing is referenced to the receive
satellite clock. The RX and TX data rates must be programmed to the same value,
and the send clock timing will have the accuracy of the receive satellite clock
(
± 100 PPM max).
2. If the Asymmetrical Loop Timing (ASLT) option is selected, either via the front
panel or remotely, the send clock timing output is referenced to the receive
satellite clock. The RX and TX data rates must be a multiple of 1 kHz if the data
rate is
≥ 64 kbps and ≤ 5 Mbps, or a multiple of 600 Hz it the data rate is ≥ 2.5
kbps and < 64 Mbps.