Anritsu 37 D Series, Maintenance Manual

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6-4
FREQUENCY
CALIBRATION
This procedure uses the internal VNA diagnostics and calibration
menus, in conjunction with a suitable frequency counter (refer to
Table 1-1), to adjust the signal source frequencies throughout the
range of the VNA model being calibrated. Perform this calibration pro-
cedure if:
q
The Source FM/Lock Linearity test in Chapter 4, Operational
Performance Tests, fails.
q
Other testing or troubleshooting reveals a possible problem with
the signal source frequency accuracy or phase lock loop.
q
Any of the following assemblies are replaced:
n
A21A1 Source YIG/Bias
n
A21A2 Source Controller
n
Down Converter
n
YIG Oscillator
n
Switched Filter
q
BBRAM chip on the A9 Processor PCB is replaced and the Source
Calibration Data was not previously saved on disk (thus data
could not be recalled from disk).
Calibration
Procedure
Perform the following steps:
Equipment Required:
Refer to Table 1-1 for further information about the following equip-
ment:
q Anritsu MF241XB Frequency Counter or equivalent EIP brand
counter equipped with Band 3 Input and GPIB capability
q RF/Microwave Cable
q GPIB cable (Anritsu 2100-2, or equivalent)
NOTE
Allow the VNA and Frequency Counter to warm-up for at
least 30 minutes prior to performing this calibration.
ADJUSTMENTS FREQUENCY CALIBRATION
37XXXD MM 6-7