TB 9-6625-2250-35
Paragraph
Page
Noise sidebands ...................................................
Frequency readout and frequency count
marker accuracy ................................................
Frequency span accuracy.....................................
Frequency response .............................................
Frequency response (alternate technique) .........
Residual responses ...............................................
Frequency drift ....................................................
Marker amplitude accuracy ................................
Power supply ........................................................
Final procedure ....................................................
IDENTIFICATION AND DESCRIPTION
1. Test Instrument Identification.
This bulletin provides instructions for the
calibration of Spectrum Analyzer, AN/USM-489A. TM 11-6625-3250-40 was used as the
prime data source in compiling these instructions. The equipment being calibrated will be
referred to as the TI (test instrument) throughout this bulletin.
a. Model Variations. There are at least 25 different AN/USM-489A versions fielded.
While there are no operational differences between versions, there are internal differences
that are maintenance significant. Therefore, the only internal adjustments included in this
procedure are for the calibrator and power supply. Additional adjustments are contained in
TM 11-6625-3250-40.
b. Time and Technique. The time required for this calibration is approximately 6
hours, using the dc and low frequency and microwave technique.
prescribed by TB 750-25.
b. Adjustments to be reported are designated (R) at the end of the sentence in which
they appear. When adjustments are in tables, the (R) follows the designated adjustment.
Report only those adjustments made and designated with (R)
pertain to this calibration are listed in table 1.
