NORMARC NM 7000 Series, Installation & Commissioning Handbook

Page: 140 / 189

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Figure 1-4 Power balance SBO illustration.
Perfect power balance between the 90 Hz modulated carrier and the 150 Hz modulated car-
rier is indicated when the two largest sets of peak waveforms fall on lines paralell to the base-
line.
A more accurate way of observing a power balance error is to double the sweep rate in non-
trigger mode such that the second 60 Hz half of the cycle is folded back on the first half and
tracks the envelope waveform. (Kissing pattern method)
RF Power Balance can be adjusted by potentiometer RF-BAL on the back of the LPA/GPA
Adjust until both halvs fall on the same envelope waveform or the two largest sets of peak
waveforms fall on lines paralell to the baseline.
1.2.5 RF Phase at Combiner I/P
Connect the oscilloscope to the BNC test connector labelled SBO located on the transmitter
modules.
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Set the oscilloscope in normal trigger mode such that the waveform below can be observed
.
Figure 1-5 RF phase SBO illustration.
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