HP 8568B Voltage-TunedOscillator Adjustments, MHz, Figure 3-78.50 MHz Voltage-TunedOscillator Adjustments Setup

20.50 MHz

Voltage-Tuned Oscillator Adjustments

Reference

Related Performance Test

Description

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

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Equipment

Procedure

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