Motorola MTR2000 T5544 Instruction / Field Service Manual page 168

METERING
CIRCUITRY
VARIOUS
SIGNALS
FROM
EXCITER BOARD TO
BE MONITORED
P/O
P3601
A/D
CHIP
13
SELECT
FROM SCM
P/O
P3601
SYNTH
ADAPT 8
FROM SCM
SPI BUS SPI BUS (CLOCK & DATA)
TO/FROM
SCM
SYNTHESIZER
CIRCUITRY
P/O
P3601
2.1 MHz
2.1 MHz REF
REFERENCE
21 PHASE
R
FROM SCM
IN
BUFFER LOCKED
LOOP IC
P/O
P3601
REF AUDIO
REF MOD
M
4
DELAY IN
FROM SCM
EQUALIZATION
F
IN
P/O
P3601
SYNTH
CHIP
18
SELECT
FROM SCM
P/O
P3601
VCO AUDIO
3
FROM SCM
A/D SPI BUS (CLOCK & DATA)
CONVERTER
(METERING)
CHIP
SELECT
AUX1
UP
LO-PASS
CHARGE
LOOP
PUMP
FILTER
DOWN
CHIP
SELECT
DIVIDER
BUFFER
SPLATTER
FILTER
REGULATOR
CIRCUITRY
+15 V
FROM
SCM
+8 V
FROM
BACKPLANE
(VIA SCM)
+10 V
FROM
BACKPLANE
(VIA SCM)
VCO
CIRCUITRY
VCO
BANDSHIFT
SELECT
CIRCUITRY
VCO CIRCUITRY (UPPER 1/2 OF BAND)
OSCILLATOR
MODULATION
STEERING LINE
CONTROL VOLTAGE
+2.5 TO +11.0VDC
VCO CIRCUITRY (LOWER 1/2 OF BAND)
OSCILLATOR
MODULATION
VCO FEEDBACK
MODULATION LOW PASS
FILTER/
ATTENUATOR
+15V SOURCE
+15 V
FOR SYNTH
FILTER
CHARGE PUMP
+5V +5V
REGULATOR SOURCE
+10 V +10V
FILTER
SOURCE
+10V
SUPER
FILTER
+8.7V
+8.5V
RF ISOLATION
CIRCUITRY
BUFFER
AMP
TX ENABLE
PIN
DIODES
BUFFER
AMP
RF SWITCH
CIRCUITRY
+8.5V
BUFFER
AMP
Figure 2. VHF Exciter Module Functional
68P81096E22-C
09/30/05
VHF Exciter Module
P/O
P3601
TX ENABLE
11
FROM SCM
J3000
BNC
MODULATED
RF OUTPUT
TO POWER
AMPLIFIER
MODULE
Block Diagram
7