Comtech EF Data SFC4200 - Manual (Page 24)

Operation SFC4200/SFC1275G Synthesized Frequency Downconverter
3-8 TM054 - Rev. 4.0
Table 3-7. SFC 1275G/SFC4200 Power Supply
+9 VDC +15 VDC +5 VDC
3048 Controller 300 ma 50 ma
3072 Ref. Assy 100 ma 300 ma
1
st
Mix U/C 120 ma 150 ma
2
nd
Mix U/C 350 ma 90 ma
Synthesizer 500 ma 850 ma
LCD Display 180 ma
Total Current 1.05 A 1.09 A 850 ma
Power 9.45 Watts 16.35 Watts 4.25 Watts
Total Power: 28 Watts * 85% Conversion Efficiency = 33 Watts Primary
Consumption
3.6 Frequency Accuracy
The 10 MHz reference in the SFC4200 was factory set for an accuracy of 1x10 E
-9
. The aging
specification of the reference is 5x10 E
-10
per day. In one year, the frequency may drift as much
as 6x10 E
-9
.
To correct an error in frequency, the operator should use the Reference Menu and adjust the
Frequency Offset in PPB. Scaling of the PPB Offset allows for
±
999 PPB of adjustment. An
increment of 1 PPB of the Reference Menu Offset will provide approximately 4.6 Hz correction in
the synthesizer frequency.
3.7 Amplitude Accuracy
The frequency response stability of the converter is not expected to vary more than the specified
accuracy of the converter over its normal life. In the event that the accuracy of the converter
gain should exceed an acceptable level, it is recommended that the unit be returned to the
factory for gain calibration. Calibration of the converter is performed under computer control.
Manually performing a calibration in the field is possible but may be considered impractical.