Maintenance; Introduction; Test Equipment - HP 3320A Operating And Service Manual

Model 3320A/B
Section V
SECTION V
MAINTENANCE
NF
_ _ R
2000
F
O
XN MIxER
FR
2000 F R
FR
20MHz
-;. 2000
REFERENCE
OSCILLATOR
The XN cirCUitry is controlled by a phase lock loop. If
either the
7
2 K or the XN number is incorrect, the loop
will not lock. The following formula can be used to derive
FO:
5-4. The tcst equipment required for the majntenance of
the 3320A/B is listed in Table 5-1. If the recommended
model is not available, use a substitute that meets the
required characteristics.
5-3. TEST EQUIPMENT.
5-1. INTRODUCTION.
5-2. This section contains the information necessary for
maintenance of the Model 3320A/B Frequency Synthe-
sizer. Included is a list of test equipment required,
in-cabinet performance tests for standard and options,
adjustment procedures for standard and options, and front
panel disassembly procedures.
NOTE
To insure proper stabilization of all circuitry,
allow a 30-minu te warmup period before begin·
ning any performance tests or adjustment pro-
cedures.
5-5. PERFORMANCE TESTS.
5-6. The following performance tests compare the
3320A/B performance with the list of specifications given
in Table 1-1. These tests may be used for incoming
inspection, periodic maintenance. or to verify specifications
after repair. A Performance Test Card is provided at the end
of this section for recording the performance of the
instrument during the performance tests. The card may be
removed from the manual as a permanent record. If the
instrument fails to meet any of its specifications, perform
the adjustment procedures outlined in Paragraph 5-27.
During the performance test, periodically vary the line
voltage ± 10% with a power line transformer to insure
proper operation at various ac line voltages. When checking
the performance of Option 001, use a 75 ohm to 50 ohm
adapter on the output of the 3320A/B (excluding Para-
graphs 5-17 and 5-21). Refer to Figure 5-7 for part numbers
and diagram of 75 ohm to 50 ohm adapter.
5-7. Frequency Accuracy. Vernier Out.
5-8. This performance test insures the 3320A/B meets the
Frequency Accuracy performance specifications listed in
Table 1-1 when the vernier control is in the out position.
The output frequency of the 3320A/B is derived from the
20 MHz Oscillator as follows:
=
FR(N- 2000)
=
FR (K)
2000
If FO
=
FR(K) and if the phase lock loop is locked up,
any frequency error in FO must be due to FR (20 MHz).
This performance test measures the accuracy of the 20 MHz
Reference Oscillator and the output of the 3320A/B to
insure phase lockup. The Frequency Accuracy specification
listed in Table I-I with the Vernier out·is ± 0.001% of
selling.
a. Connect an electronic counter to the 1 MHz output
jack on the 3320A/B rear panel. The counter indication
should be 1.000000 MHz
±
10 Hz.
b. Connect the counler to the 3320A/B front panel
OUTI'UT jack.
c. Set the 3320A/B RANGE to MHz and FREQUENCY
to 12.22. Set VERN IN/OUT to VERN OUT. The counter
indication should be 12.220000 MHz ± 122 Hz.
d. Set the 3320A/B FREQUENCY to 1.10. The counter
indication should be 1.100000 MHz ± II Hz.
e. Set the 3320A/B FREQUENCY
to
00.01. Set the
counter TIME BASE to .1
IlS
and FUNCTION to PERIOD
AVERAGE 10K. The counter indication should be
100.00000
IlS
± 1 ns.
5-9. Frequency Accuracy. Vernier In.
5·10. The 3320A/B uses two unrelated reference oscillators
to derive the output frequency when the vernier control is
5-1