
Correction Constants and Firmware 8712ET/ES and 8714ET/ES
Storing and Recalling Correction Constants (CC) RF Network Analyzers
8-2 Service Guide
Storing and Recalling Correction Constants (CC)
NOTE Firmware and correction constants reside in segmented flash EPROMs.
Because the EPROMs are segmented, it is possible to upgrade either
firmware or correction constants independently.
Figure 8-1 Correction Constants Flow by Keystroke and Cycling Power
Correction constants are what give the analyzer its accuracy as well as its default
calibration. Incorrect or missing correction constants will result in the following poor
performance:
• non-zero transmission trace when a good quality through cable is connected
• non-zero return loss measurement with a short or open circuit
• poor directivity
• output power inaccuracy
Analyzer-specific correction constants are provided with each instrument shipped from the
factory. The correction constants are provided on a 3.5" floppy disk and consist of one file
that is about 25 kilobytes in size. Although each file is serial number specific, the same file
name is used for each analyzer. Since this is the case, files for different instruments must
remain stored on different disks. It is important that the proper disk be used with the
proper instrument.
Do not format or re-use the correction constants disk shipped with the analyzer unless you
are certain that the data on it is no longer needed. In general, correction constants cannot
be totally erased; they can only be updated (overwritten). The disk shipped with each
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