Rssi (Received Signal Strength Indicator); Transmitter Power; Transmit Deviation Balance (Compensation) & Deviation Limit; Transmit Deviation Limit - Motorola GTX 2000 Service Manual

GTX/GTX LTR/LTS 2000 Portable Radios Service Manual
3. Adjust the UP/DOWN arrow key to the mini-
mum squelch value.
4. Set the RF test generator to the test frequency
plus +500 Hz offset.
5. Adjust the UP/DOWN arrow key until the
squelch just closes.
6. Monitor for squelch chatter; if chatter is
present, continue to adjust the UP/DOWN
arrow. Wait a few seconds and repeat step 7.
7. When no chatter is detected, press F8 to pro-
gram this value. Press ÒENTERÓ to select next
softpot adjustment.
8. Press F10, F10 to return to the Service menu.

RSSI (Received Signal Strength Indicator)

Here are the tuning procedures for the SmartZone
Models.
1. Press F2 to select LOGIC or RF BOARD
2. Press F8 to select SQUELCH/RSSI.
3. Press F10 to select RSSI.
4. Set Signal Generator to 870.1625 MHz.
5. Set RF level to -106dBm.
6. Press F4 to read the RSSI digital value dis-
played on the top right side of the screen.
7. Type this value in the appropriate place on the
screen.
8. Repeat steps 6 to 7 with RF levels of -90dBm
and -74dBm.
9. Press F8 to program the values.

Transmitter Power

1. From the SERVICE menu, press F2 to select
ALIGNMENT: TRANSMITTER & RECEIVER.
2. Press F7 to select the Tx POWER calibration
softpot. The screen will indicate the transmit
test frequencies to be used.
3. Press F6 to key the radio, and use the UP/
DOWN arrow keys to adjust the transmit
power value. Press F6 to dekey the radio.
Press ENTER to select next softpot frequency.
4. Press F8 to program the value.
5. Press F10, F10 to return to the SERVICE menu.
Transmit Deviation Balance
(Compensation) & Deviation Limit
Compensation alignment balances the modulation
June 1999
sensitivity of the VCO and reference modulation
(synthesizer low frequency port) lines. Compensation
algorithm is critical to the operation of signaling
schemes that have very low frequency components
(e.g. DPL) and could result in distorted waveforms if
improperly adjusted.
1. From the SERVICE menu, press F2 to select
ALIGNMENT: TRANSMITTER & RECEIVER.
2. Press F3 to select the transmit deviation bal-
ance and deviation limit softpot. The screen
will indicate the transmit test frequencies to
be used.
3. Begin with the lowest test frequency shown
on the screen.
4. Press F4 to select 60 Hz.
5. Press F6 to key the radio. Record this meas-
urement.
6. Press F6 again to dekey the radio, and press F4
to select 2.5 kHz.
7. Press F6 to key the radio, then use the UP/
DOWN arrow keys to adjust the deviation
until the value in step 5 and the value in step 6
are equal.
8. Press F6 to dekey the radio. Press ENTER to
move to next softpot value.
9. Press F8 to program the softpot value.

Transmit Deviation Limit

The transmit deviation limit softpot sets the maximum
deviation of the carrier. Tuning is performed for 25
kHz channel spacing.
1. Press F10 to select the DEVIATION LIMIT
ADJUSTMENT softpot. The screen will indi-
cate the transmit test frequencies to be used.
2. Begin with the lowest test frequency shown
on the screen.
3. With Test Box RTX4005A: inject a 1 kHz tone,
2000 mVrms.
4. Press F6 to key the radio, and use the UP/
DOWN arrow keys to adjust the deviation to
between 4.4 kHz and 4.8 kHz.
5. Press F6 to dekey the radio. Press ENTER to
move to the next softpot value.
6. Press F8 to program the softpot value.
7. Press F10, F10 to return to the SERVICE menu.
68P02945C75-A
Radio Tuning Procedure
Tuning Procedure
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