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30w MS
HP 8663A
SYNTHESIZED SIGNAL GENERATOR
(Including Options 001, 002, & 003)
Service Manual
VOlUwlG4
SERIAL NUMBERS
This manual applies directly to imt.rumentS with
serial numbers pr&xed:
2234A to 2927A and all MAJOR changesthat apply to your instrument.
rev.01JULSI
For additional irqrtant information about serial
numbers, refer to "INSTRUMENTS COVERED BY
THIS MANUAL" in Section 1.
Third Edition
This material may be reproducedby or for the U.S.
Government pursuant to the Copyright License un-
der the clause at DFARS 52.227-7013(APR 1988).
Copyrighl@HEWLETT-PACKARD COMPANY 1982
EAST 24001 MISSION AVENUE, TAF C-34, SPOKANE, WASHINGTON, U.S.A. 99220
Service Manual (Volume 1, 2, 3, 4) HP Pal 08663-90071
Other Documenls Available:
Operation and Calibration Manual HP Part 08663-90069
Microfiche Service Manual Parr 08663-90072
HP
MIcrofiche Operation and Calibration Manual HP Part 06663-90070 Printed In U.S.A. : November 1990
HEWLETT
PACKARD
COPYRIGHT AND DISCLAIMER NOTICE
Copyright - Agilent Technologies, Inc. Reproduced with the permission of Agilent
Technologies Inc. Agilent Technologies, Inc. makes no warranty of any kind with regard
to this material including, but not limited to, the implied warranties of merchantability
and fitness for a particular purpose. Agilent Technologies, Inc. is not liable for errors
contained herein or for incidental or consequential damages in connection with the
furnishing, performance, or use of this material or data.
Model 8663A Service
SERVICE SHEET 38
AllA FM PHASE DETECTOR
REFERENCEBLOCK DIAGRAM 7
Table 4-l. Recommended Performance Tests
After Adjustments or Repairs
Table 5-2. Post-Repair Adjustment Procedures
PRINCIPLES OF OPERATION
General
The purpose of the FM Phase Detector (AllA4) is to develop the FM
Loop Error Voltage. This is accomplished by comparing the VCO output
with a 10 MHz reference signal.
Phase Detector Circuitry
The Phase Detector Circuitry compares the phase difference between
the reference signal (FM 10 MHz Reference Signal) and the output of
the VCO (FM Loop N-Divider Drive), then generates a voltage
proportional to the phase error. Both input signals are first
divided down to 100 kHz before they are compared by the FM Loop Phase
Detector, U4. The 10 MHz signal from the Reference Section is
divided by a total of 100. This signal becomes the reference input
to the phase detector. The 140 MHz VCO output is divided by a total
of 1400. This signal becomes the variable input to the phase
detector.
The Phase Detector, U4, is a digital phase detector that generates
output pulse widths proportional to the phase difference between the
two input signals. If the variable 100 kHz signal is lower in
frequency or lags the reference input in phase, the output on pin 13
generates a pulse (See Figure 8-601). When the variable input is
higher in frequency or leads the input in phase the output on pin 2
generates a pulse (see Figure 8-602).
Figure 8-601. Phase Detector Operation
(Variable Input is Lower in Frequency than Reference S&vml)
8-601