MTR3000 Programming and Tuning: Modulation Limit Alignment 13-15
8. Adjust the softpot value until the maximum deviation is 92% of the rated system deviation
(RSD). This will be tested in a 12.5 kHz channel spacing, so 92% of 2.5 kHz is 2.3 kHz.
9. Click the “PTT Toggle” button within the Tuner environment to de-key the radio.
10. Click “Write” to save the new tuned softpot value into the radio’s codeplug.
13.6.2 Verification (with no Tx Data and no PL)
1. Connect the radio’s antenna port to the attenuation pad, if necessary, before connecting to
the Communication Analyzer.
2. Power the base station/repeater from either an AC or DC source.
3. Via CPS, program the radio with any frequency within the specified range of the base station/
repeater under test, and set the radio for low power and disable the repeat path.
4. Apply a 1 kHz signal at 1.2 Vrms to Pin 1 of the J7 backplane connector.
- Signal ground is Pin 9 of the J7 backplane connector.
5. Key up the radio and measure the deviation
- Key the radio by grounding Pin 2 of the J7 backplane connector.
- CPS must have Pin 2 configured as an active low with the PTT function.
6. De-key the radio.
The deviation shall meet the limits shown in the table below.
Note
Set the modulation limit to 92% so that any additional deviation incurred by the transmitter
VCOs over temperature is compensated for.
Channel Spacing RSD 92% of RSD Tolerance
12.5 kHz 2.5 kHz 2.3 kHz +0Hz / -50Hz
Channel Spacing
Relative
Standard
Deviation
(RSD)
92% of RSD Tolerance
12.5 kHz 2.5 kHz 2.3 kHz +0Hz / -50Hz
20.0 kHz 4.0 kHz 3.68 kHz +0Hz / -80Hz
25.0 kHz 5.0 kHz 4.6 kHz +0Hz / -100Hz
Note The base station/repeater will be factory-tuned in accordance to the above procedure and
specification.
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