Adjusting The Exciter Output Level - Codan NGT 2010 RF Technical & Service Manual

NGT—Checks and adjustments

Adjusting the exciter output level

Drawing
ALTERNATIVE TEXT
NOTE
NOTE
To adjust the exciter output level:
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Figure 40: Setup for test unit with a 2010/2012 RF Unit
generator
Figure 41: Setup for test unit and NGT test handset with a 2011 RF Unit
generator
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170
08-05261 (sheet 2)
If the PCB issue status is -06 or earlier, see drawing
The transceiver must be in Service mode to perform this check (see
page 154, Accessing Service
Unplug the coaxial cable between the PA PCB and RF/IF PCB in the RF unit.
Connect a 47 Ω resistor from the Tx test point to ground on the RF/IF PCB.
Connect an oscilloscope to the Tx test point.
Connect a signal generator to provide two-tone audio (700 Hz and 2300 Hz) via the
test unit to:
• the audio input on the 15-way GPIO connector on the junction box or 2012 RF
Unit (see Figure 40), or
• the 2011 RF Unit via the NGT test handset (see
Signal
Signal
Select test channel 16 with USB mode.
Hold down PTT, then adjust the level of the two tones for compression.
Adjust the Y sensitivity of the oscilloscope for on-screen display, and adjust the
trigger for a stationary waveform.
Adjust the two-tone balance control for good crossover display.
Adjust the Tx level control (R256, near the ribbon cable) for a level of 650 mV p–p
on the oscilloscope (see
Release PTT.
or 08-05889 (sheet 2)
mode).
2030 Junction Box
Test unit with 2010 RF Unit,
or 2012 RF Unit
NGT test
Test unit
handset
Figure 28 on page 160
NGT Transceiver System Technical Service Manual
08-05889 (sheet
Figure 41)
2011 RF Unit
or Figure 29 on page 161).
2).