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20. 50 MHz
Voltage-Tuned
Oscillator
Adjustments
Reference
Related Performance
Test
Description
Equipment
Procedure
RF Section:
All 50 MHz Voltage-Tuned Oscillator (VTO)
Frequency Span Accuracy Test
Center Frequency Readout Accuracy Test
First, the voltage reference for the Shaping network is set by
measuring the voltage required to tune the 50 MHz Oscillator to its
high limit (57.5 MHz) and then setting the reference voltage (+ 15 VR)
to that voltage.
Next, the VT0 tuning accuracy is adjusted at both the low and high
end by setting the tune voltage to the proper levels to tune the VT0
to its low and high end limits (42.5 MHz and 57.5 MHz). This is done
using the output of the tuning DACS from the
A22
Frequency Control;
therefore, it is necessary that the DAC adjustments on the Frequency
Control have been performed before adjusting the 50 MHz VTO.
SPECTRUM ANALYZER
DIGITAL VOLTMETER
peJy$jjqy
Figure 3-78. 50 MHz Voltage-Tuned Oscillator Adjustments Setup
Digital Voltmeter (DVM) . . . . . . . . . . . . . . . . . . . . . . . . HP
3456A
1. Position Instrument on right side as shown in Figure 3-78 and
remove bottom cover. Remove All 50 MHz Voltage-Tuned
Oscillator and place on extenders.
2. Set LINE switch to ON and press [INSTR PRESET).
3-130 Adjustments