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30
Transmitter Alignment
transmitters with flat audio
Section a: Balanced and Subtone audio Setup
Step
Reference
1.
R2 (Mic I/P)
R29 (Deviation)
R31 (Balanced)
R38 (Compress)
R42 (Subtone1)
R63 (Mic Comp)
R36 (TCXO)
2.
Balanced Input
P1-1 and P1-2
3.
R29 (Deviation)
4.
Subtone 1 input
5.
R42 (Subtone1)
6.
OST-3H035-(2-Port)
OST-3H045-(2-Port)
7.
R36 (TCXO)
8.
Subtone 1 input
9.
Deviation Monitor
10.
Deviation Monitor
11.
AF Gen
12.
R31 (Balanced)
Section B: microphone audio Setup
Step
Reference
13.
Microphone Input
Front Panel Pin 2
14.
R2
MT-3 FM Transmitter Mainboard Instruction Manual
IM20-MT3TXMN
Action
Turn Fully CW.
Turn Fully CW.
Turn Fully CW.
Turn Fully CW.
Turn Fully CW.
Turn Fully CW.
Turn Fully CCW.
Set AF Gen. freq, level
and filter.
Adjust R29 for deviation.
Do not re-adjust.
Apply tone.
Adjust and measure.
Change AF Gen. freq.
Adjust and measure.
Change AF Gen. freq.
Should measure.
Sweep AF Gen. freq.
between 67 Hz and
250 Hz. Measure
resultant deviation.
Change level.
Adjust and measure.
Action
Change level.
Adjust and measure.
Desired Results
Notes
AF Filter: Low Pass
5 kHz or 15 kHz
NO COMPRESSION
NO COMPRESSION
AF Gen: 1.8 kHz @ +10 dBm
± 4.4 kHz
AF Gen: 1 kHz Tone @ -18 dBm
± 500 Hz
Deviation Monitor
AF Gen:
40 Hz @ -18 dB
± 500 Hz
AF Gen:
300 Hz @ -18 dBm
500 Hz
Tolerance on this
measurement is ± 50 Hz
± 300 Hz to 700 Hz
1 kHz Tone @ -8 dBm
± 3 kHz
Deviation Monitor
Desired Results
Notes
AF Gen: 1kHz Tone
@ -10dBm
MIC Connector - Front View
± 3kHz
Deviation Monitor
MIC AUDIO
3
2
MIC GND
4
1
FRONT VIEW
DANIELS
A
1
2
3
4
5
6
7
8
9
10
TM
11
12
13
14
15
16
17
18
19
20
ELECTRONICS LTD
21
22
23
24
25
26
27
28
29
30
TITLE: TX MICROPHONE CONNECTOR DETAILS
DATE: 28 MARCH 2005
DRAWN BY: EVA DANIELS
REV DATE: - - -
DWG No: B0486-01
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