controls to obtain a display of
setup.
proper connection in test setup.
frequency response of passive
device under test.
3
Adjust and level-set sign a
Oscilloscope displays zero-beat
Defect within signal source no. 2.
Refer to paragraph 3-13 of this
source no. 2 so that a zero-beat
marker at point of interest on
section and to BWO power
marker appears at point of in-
frequency response pattern.
supply manual.
terest on oscilloscope display.
Poor or improper connection in
Locate and correct poor or im-
test setup.
proper connection.
Defective component in test setup.
Locate and replace defective
component.
4
Phase-lock signal source no. 2.
Signal source phase-locks as indi-
Defect within tunable synchronizer
Refer to tunable synchronizer
cated on tunable synchronizer.
mannual.
5
Determine input signal level by
Zero beat display on oscilloscope.
Frequency converter overdriven or
Adjust attenuation of level-set at-
using the signal input level to
input from unit under test too
tenuator.
frequency converter chart in
low.
chapter 2, section II, of TM
Adjust output of unit under test
9-4931-15/1 and adjust level-
set attenuator accordingly
Defect within frequency converter.
Refer to frequency converter
Connect VID OUT connector
manual.
on frequency converter to CH
Defect within oscilloscope.
Refer to oscilloscope manual.
2 input connector on oscillo-
scope. Adjust oscilloscope for
Poor or improper connection in
Locate poor or defective connec-
best display of channel 2
test setup.
tion and correct
input Tune frequency con-
verter in direction of decreas-
ing frequency until the first
zero beat is observed.
6
Adjust' MIXER TUNE stubs for
Zero-beat amplitude increases. ;
Defect within frequency converter.
Refer to frequency converter
maximum amplitude of zero
manual.
beat
Defect within oscilloscope.
Refer to oscilloscope manual.
7
Adjust level-set attenuator as re-
Zero-beat amplitude increases.
Defect within frequency converter.
Refer to frequency converter
quired to obtain sufficient am-
manual.
plitude of zero beat.
8
Adjust main and FINE TUN-
Zero beat remains steady.
Defect within frequency converter.
Refer to frequency converter
ING controls on frequency
manual.
converter for precise zero beat
as indicated on oscilloscope.
Unit under test unstable.
Troubleshoot unit under test.
9
Note digital counter readout at
Frequency display on digital
Defect within digital counter.
Refer to digital counter manual.
zero beat and record five most
counter.
significant figures, fL.
10
Tune frequency converter to next
Zero beat on oscilloscope and fre-
Defect within digital counter.
Refer to digital counter manual.
lower zero beat and record five
quency display on digital
most significant figures, fL.
counter.
3-7
