22
Transmit
Deviation Balance
(Compensation)
Compensation alignment balances the modulation sensitivity of the
VCO and reference modulation (synthesizer low frequency port) lines.
The compensation algorithm is critical to the operation of signalling
schemes that have very low frequency components (e.g. DPL) and
could result in distorted waveforms if improperly adjusted.
NOTE: Disable all audio band filters on the service monitor.
NOTE: (Secure-Equipped Radios Only)
If a secure module is currently installed in the radio
being aligned, refer to the appendix at the rear of this
manual. Read section III, “Secure Alignment
Procedure”, before performing the transmit deviation
balance (compensation) procedure.
1. Press F4 to select the TRANSMIT DEVIATION BALANCE softpot.
The screen will indicate the transmit test frequencies to be used.
2. Begin with the lowest test frequency shown on the screen.
3. Set the Test Box (RTX4005B) meter selector switch to the “MX
DISC” position, and inject an 80Hz tone at 100mVrms into the
AC/DC MTR port. Keep the ac voltmeter in parallel to ensure the
proper input signal level.
4. Press F6 to key the radio, and measure deviation. Record this
measurement.
5. Change the input tone to 3 kHz, 100mVrms and use the UP/
DOWN arrow keys to adjust the deviation to within ±2% of the
value recorded in step 4.
6. Change the input tone back to 80 Hz and measure the deviation.
7. Repeat steps 5 and 6 until the 3kHz tone deviation is within ±2%
of the 80Hz tone deviation.
8. Press F6 to dekey the radio, and press F8 to program the softpot
value. Press ENTER to move to next softpot value.
Table 15 Transmit Power Setting
VHF
UHF
Power Level
Test Frequencies
Power Level
Test Frequencies
136 - 174MHz
177.975MHz
450 - 512MHz
512 - 520MHz
5 W
5.2 - 5.4
4.2 - 4.4
4 W
4.2 - 4.4
3.2 - 3.4
1 W
1.2 - 1.4
1.2 - 1.4
1 W
1.2 - 1.4
1.2 - 1.4
800 MHz
900 MHz
Power Level
All Test Frequencies
Power Level
All Test Frequencies
3 W
3.2 - 3.4
2.4 W (Typ.)
2.9 W (Max.)
2.4 - 2.6
Содержание SYMBOL MT2000 Series
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Страница 147: ...Appendix A 9 Appendix Figure 2 Secure Module Location Detail ...
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