artisan 8640B - Variable-Frequency Modulation Oscillator Adjustment (Option 001)

Model 8640B TM 9-4935-601-14-7&P
ADJUSTMENTS
5-26. FIXED-FREQUENCY MODULATION OSCILLATOR ADJUSTMENT (Cont'd)
EQUIPMENT:
Digital Voltmeter .......................................................................HP 3480B/3484A
600 Ohm Feedthrough .......................................................................HP 11095A
PROCEDURE:
1. Connect DVM, to AllTP3 (AM out). Set Signal Generator's controls as follows:
AM................................................................................................................. INT
MODULATION FREQUENCY.................................................................1000 Hz
FM ................................................................................................................OFF
AUDIO OUTPUT LEVEL...........................................................................Full cw
2. Adjust OSC LEVEL adjustment, AllR6, for a 840 +10 m Vrms reading on DVM at AllTP3.
3. Connect DVM, through 600 ohm feedthrough, to AM OUTPUT. Set AUDIO OUTPUT LEVEL to 100 m Vrms as
read on DVM. The AUDIO OUTPUT LEVEL dial should read 100 m Vrms. If it does not, loosen setscrews on
knob and align knob so that it does.
4. Set MODULATION FREQUENCY to 400 Hz. Set AUDIO OUTPUT LEVEL fully cw. The DVM should read > 1
Vrms.
1 Vrms
5-27. VARIABLE-FREQUENCY MODULATION OSCILLATOR ADJUSTMENT (OPTION 001)
REFERENCE:
Service Sheet 9A.
DESCRIPTION:
A digital voltmeter and a frequency counter are used to monitor output voltage and frequency while adjusting the
oscillator. The MODULATION FREQUENCY dial and the AUDIO OUTPUT LEVEL dial are adjusted.
EQUIPMENT:
Digital Voltmeter .......................................................................HP 3480B/3484A
Frequency Counter...............................................................................HP 5327C
600 Ohm Feedthrough .......................................................................HP 11095A
5-9
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