Anritsu 37 D Series, Maintenance Manual, Page: 18 / 190

Internal Hardware
Adjustments and
Calibrations
There are five automated internal hardware field calibrations. Two of
them are used to characterize the VNA frequency and power genera-
tion sub-systems. These calibrations insure fast, consistent phase lock
of system frequencies and proper compensation, leveling, and flatness
of system power at the front panel test ports.
To conduct these calibrations, you need only connect the appropriate
test equipment (counter or power meter) to the VNA and initiate the
calibration. The VNA will control itself and the externally connected
test equipment to perform measurements and store calibration con-
stants in its internal battery backed RAM (BBRAM).
The procedures for adjusting the VNA are described in this manual in
Chapter 6, Adjustments.
Internal Service Log The VNA continuously monitors itself for proper operation. Should a
failure occur, it notifies the user via a failure message on the display
screen. (In remote-only operation, it also sets the GPIB Status Byte, if
enabled.) It also writes the error message along with some data perti-
nent to the failure to an internal service log stored in battery backed
memory.
The service log can be checked at any time to view (without erasing)
all error messages that were written into it. It is capable of storing
more than 30 pages of service messages and data. The VNA will auto-
matically remove the oldest errors first to make room for new errors, if
necessary. To check the contents of the service log, use the procedure
described in Chapter 4, Operational Performance Tests.
NOTE
A printed or disk file copy of the Service Log (with the failure
in question) must be made available to Anritsu when ex-
changing a failed assembly, or when requesting service sup-
port. Refer to Chapter 2, Replaceable Parts, for further
information.
SERVICE STRATEGY GENERAL INFORMATION
1-6 37XXXD MM