Comtech EF Data SNM-1010L - Manual (Page 261)

SNM-1010L Data/Control Modem Revision 0
Specifications
MN/SNM1010L.OM
B.8 BUC FSK Communications
The modulator includes capability to communicate with an ODU Block Up Converter
(BUC) using an FSK signal multiplexed onto the IF output connector along with the TX
IF signal, 10 MHX reference, and DC power to the BUC. The M&C implements
commands to control BUC functions and to query the BUC for configuration or status
information.
FSK Transmitter
Frequency
650 kHz ± 5 %
FSK Deviation ± 60 kHz nominal (+60 kHz mark)
Deviation Tolerance ± 50 kHz minimum, ± 70 kHz maximum
Output Level -5 to –15 dBm
Start Tone Time 10 ms minimum
Output Impedance 50 Ω
Start Time 710 kHz
FSK Receiver
Locking Range
Input Sensitivity
± 32.5 kHz
-15 dBm (50
Ω)
Transmission Protocol
Baud Rate
Data Bits
Parity
Stop Bits
Message Rate
BUC Response Time
Maximum Response Time
9600 bps
8
None
1
1 every 40 msec
12 msec, typical
40 msec
Note: If the BUC does not respond within the maximum response time the IDU should cyclically
repeat the command.
On powerup, the TX carrier is Off until the BUC is commanded to turn the carrier on
(unless the unit is commanded into the power On mode at the factory). The BUC does
not allow the carrier to be turned On unless the PLL is locked, and automatically turns
the carrier Off in the event the PLL goes out-of-lock. If the PLL then comes back into
lock, the BUC restores the carrier to the most recent requested state by the IDU. The
carrier enable/disable function is implemented by switching On/Off the switched
regulators of the BUC amplifier chains (a “sleep mode”).
The BUC is equipped with a calibrated power sensor for measuring the power delivered
to the antenna for rated output to 20 dB backed off. This value, in dBm, is available via
the M&C for power level monitoring and AGC. Refer to BUC manufacturer
specifications for reported power accuracy.
B–19