controls to obtain a display of
frequency response of passive
device under test.
3
Adjust and level-set s i g n a 1
Oscilloscope displays zero-beat
source no. 2 so that a zero-beat
marker at point of interest on
marker appears at point of in-
frequency response pattern.
terest on oscilloscope display.
Defect within signal source no. 2.
Refer to paragraph 3-13 of this
section.
4
Alternately tune frequency mul-
Amplitude of zero-beat marker in-
tiplier and increase BIAS
creases
VOLTS ADJUST control until
Defect within BWO power supply
Refer to BWO power supply
maximum amplitude of marker
manual
is obtained.
5
Phase-lock signal source no. 2.
Signal source phase-locks, as indi-
Defect within tunable synchronizer.
Refer to tunable synchronizer
cated on tunable synchronizer.
manual.
Poor or improper connection in
Locate and correct poor or im-
test setup.
proper connection.
6
Determine 'input signal level by
Frequency converter overdriven or
using the signal input level to
input from unit under test too
tenuator.
frequency converter chart in
low.
chapter 2, section II, of TM
9-4931-15/1 and adjust level-
Adjust output of unit under test.
set attenuator accordingly.
Connect VID OUT connector
Defect within oscilloscope.
Refer to frequency converter
on frequency converter to CH
manual.
2 input connector on oscillo-
Poor or improper connection in
Refer to oscilloscope manual.
test setup.
best display of channel 2
Locate poor or defective connec-
input. Tune frequency con-
tion and correct.
verter in direction of decreas-
zero beat is observed.
7
Adjust MIXER TUNE stubs for
Zero-beat amplitude increases.
Refer to frequency converter
maximum amplitude of zero
manual
beat.
Defect within oscilloscope.
Refer to oscilloscope manual
8
Adjust level-set attenuator as re-
Zero-beat amplitude increases.
Refer to frequency converter
quired to obtain sufficient am-
manual
plitude of zero beat.
9
Adjust main and FINE TUN-
Zero beat remains steady..
Refer to frequency converter
ING controls on frequency
manual
converter for precise zero beat
3-9