ComStream CM601, Инструкция по установке и эксплуатации

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External Connections 3-7
The CM601 will always set the RR signal to On when the entire receive path is
locked to the receive signal and RD represents valid data. This will occur whether
the CM601 data control mode is set to Off or On (CD 1 or 2).
When the modem is set for data control mode using the CD 2 command, the data
control signals RS, TR, DM, CS, and RR are defined, as shown in Table 3-7.
Signal Quality
Signal quality is supported only by the RS-449 interface. The signal is active
when the CM601 E
b
/N
0
falls below the user-specified threshold, which is set with
the EBT command. Signal quality can be used to sound an alarm or log a fault
condition when data integrity falls below the specified threshold.
Tx IF Connector
The Tx IF connector provides the transmit IF output to the RF equipment. The
CM601 modulator has electronically adjustable output power. The output power
adjustments can be made using the front panel Tx Pwr Level command or the
remote TP command.
For normal CM601 operation, the output power of the modulator is set between -
5 to -25 dBm in 0.1-dB steps. The output frequency is programmable in the range
of 52 to 88MHz or 104 to 176MHz depending on the modem card options
ordered. The output impedance is 75 ohms with a return loss of 20 dB or better.
Rx IF Connector
The Rx IF connector is used to receive the IF signal. The power of the input signal
must be in the range of -10 to -55 dBm. The IF frequency must be in the range of
52 to 88MHz or 104 to 176MHz depending on the modem card options ordered.
Table 3-7 Data Control Signals
Data Control Signal Description
RS and TR Setting both signals to On will allow the modem to transmit. It is
recommended that RS be used as the primary transmit control line.
Setting either line to Off will disable transmission. The modem is
powered on and the DTE TR is set to On.
DM DM is set to On by the modem when data control mode is selected.
CS CS is set to On by the modem when the modulator is ready to accept
data.
RR RR is set to On by the modem when the demodulator has acquired and
is receiving valid data.