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