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Signalling Deviation Adjustment; Dtmf Encoder Microphone Deviation Adjustment - Motorola Spectra Service Manual

900 mhz two-w ay fm radios
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11. This completes TX compensation calibration
procedure. Press F10 twice to return to the
"SERVICE" menu and adjust deviation per
paragraph IV.
VII. SIGNALLING DEVIATION ADJUSTMENT
Signalling deviation should be checked any time the
radio is serviced and must be adjusted whenever any of
the modulation circuitry has been replaced. Before
adjusting signalling deviation, radio compensation/devi-
ation adjustments must be made. No adjustments are
required for PL, DPL, or trunking connect tone deviation.
1. Connect the modulation analyzer (or service moni-
tor) to the antenna connector. Set modulation
analyzer to read peak deviation.
2. Connect dc power to the radio and switch radio
power on.
3. At the PC's "MAIN MENU" prompt, press F2 to
select "SERVICE."
4. At the "SERVICE" menu, press F4 to select
"ADVANCED ALIGNMENT."
5. At the "ADVANCED ALIGNMENT" menu, press F8
to select the "SIGNALLING DEVIATION."
6. At the "SIGNALLING DEVIATION" menu, select the
desired signalling type by pressing the appropriate
key:
F3
DTMF
F4
MDC
F5
Single Tone
F6
Trunking High-Speed Data
Only the signalling types used on the radio being
aligned must be adjusted. If the radio is a dual-mode
radio, both conventional and trunking features must
be adjusted. DTMF must be adjusted if used on
either conventional or trunked modes. On conven-
tional radios without MDC or DTMF, these
adjustment procedures are not required.
Single Tone will show "HS" on the display of the
radio, since the modulation path is the same as
trunking high-speed data.
7. At the selected signalling screen, press F6 to key
the radio.
NOTE
NOTE
8. Use the up and down arrow keys to adjust devia-
tion. Stop adjustment at the deviation value closest
to the value shown below:
DTMF
MDC
Single Tone
Trunking HS
9. Press F6 to dekey the radio; then, press F8 to pro-
gram the deviation value.
10. Press F10 to return to the "SIGNALLING DEVIA-
TION" menu. Select another signalling type and
repeat steps (6) through (9). Repeat until all sig-
nalling types are adjusted.
11. This completes signalling deviation adjustment pro-
cedure. Press F10 as needed to return to the MAIN
MENU or to other SERVICE screens.
VIII. DTMF ENCODER MICROPHONE
DEVIATION ADJUSTMENT
To adjust the DTMF deviation level of a Touch-
Code
TM
encoder (DTMF) microphone, enter the front
panel test frequency menu as described in IX. TROU-
BLESHOOTING AND REPAIR paragraph of this
manual, and select the second test frequency (901.9875
MHz transmit) and carrier squelch (CS) signalling type.
(DO NOT attempt to adjust the Touch-Code microphone
deviation level while in the radio service software sig-
nalling deviation adjustment; an error will occur when
the microphone is keyed).
After selecting the proper test mode, observe the
Touch-Code DTMF deviation on a modulation analyzer
or service monitor (set for peak deviation reading) while
repeatedly pressing the "#" button. Each button press
causes the radio to transmit for 1.2 seconds. The cor-
rect deviation level is 1.87 MHz.
If adjustment is required, insert a long tuning tool
(Motorola Part No. 66-84974L01) through the micro-
phone's rear housing access hole, located to the right of
the nameplate. To set the deviation, rotate the tone
deviation potentiometer.
IMPORTANT
Set the level during the 1.2 seconds following the
press of the "#" button in order to get an accurate
reading.
1.50 kHz
1.75 kHz
1.50 kHz
1.60 kHz
33

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