Comtech EF Data SFC4200 - Manual (Page 58)

Electrical Interfaces SFC4200/SFC1275G Synthesized Frequency Downconverter
5-8 TM054 - Rev. 4.0
5.11 Monitor Ports
The SFC Downconverters have Monitor Ports located on the Front Panel (Figure 5-7) that allow
the operator to monitor the IF Input, RF Input and Synthesized LO.
Figure 5-7. SFC Downconverter Front Panel with Monitor Ports
5.11.1 RF Monitor Port
The RF Monitor port is an SMA (F) Type Connector located on the front panel. Signals present
at the RF Input of the SFC Downconverter (J1) can be monitored at the RF Monitor Port. The
power level of the monitored signal will be -15 dB nominal below the level present at J1.
5.11.2 IF Monitor Port
The IF Monitor Port is an SMA (F) Type Connector located on the front panel. Signals present at
the IF Output of the Converter (J2) can be monitored at the IF Monitor Port. The power level of
the monitored signal will be -15 dB nominal below the level present at J2.
5.11.3 LO Monitor
The LO Monitor allows the operator to monitor the Synthesized or Second Mixer Local Oscillator
using the SMA LO Monitor Connector at the front of the converter. The power level of the signal
measured will be -15 dBm nominal. The frequency of the synthesizer LO in the SFC
Downconverters can be determined by subtracting the IFLO Frequency (Table 5-5) from the
displayed transmit frequency on the LCD display.
The LO Monitor can be used to set the 10 MHz Reference with a high degree of accuracy
unobtainable by just measuring the 10 MHz Output. See Section 6, Maintenance, for more
details on setting the reference oscillator accuracy. Also, the SSB Phase Noise performance of
the LO monitor is an accurate representation of the phase noise of the entire converter. Refer to
Figure 5-9 for a Single Sideband Phase Noise Plot.
Table 5-5. IF LO Frequency
SFC4200 SFC1275G
Standard Extended
70 MHz 140 MHz 70 MHz 140 MHz
70 MHz 140 MHz
1.1825 MHz 1.8525 MHz 1.295 MHz 1.365 MHz 2.07 GHz 2.14 GHz