Figure 1. 900-Mhz Radio Functional Block Diagram - Motorola MCS 2000 Service Instructions Manual

RECEIVER
73.35 MHz
RECEIVE
RECEIVER
RF SIGNAL
FRONT END
SECTION
FIRST
RECEIVER
LOCAL
OSCILLATOR
TRANSMITTER
P/O CONTROLLER
SECTION
(NOTE 1)
AUDIO
SIGNAL
FILTER
(ASFIC)
MICROPHONE
AUDIO
OPERATOR INTERFACE (CONTROL HEAD - NOTE 2)
MICROPHONE
OPERATOR
KEYBOARD,
PUSHBUTTONS,
AND OTHER
CONTROLS
PUSH TO
TALK (PTT)
DC POWER CONTROL AND REGULATION
13.8VDC
FROM VEHICLE
BATTERY OR
BASE STATION
POWER SUPPLY
Revision B, 5/98
73.35 MHz
RECEIVER IF
IF
IF
AMPLIFIER
SECTION
2.1 MHz
REFERENCE
OSCILLATOR
AUDIO
MODULATION
SIGNAL
SYNTHESIZER
SECTION
TRANSMITTER
INJECTION
SIGNAL
ACCESSORY
INPUTS AND
OUTPUTS
CONTROL HEAD
PROCESSOR
P/O CONTROLLER SECTION
(NOTE 1)
REGULATED
CONTROL AND
DC POWER
REGULATION
CIRCUITS
Figure 1 . 900-MHz Radio Functional Block Diagram
P/O CONTROLLER SECTION (NOTE 1)
RECEIVER
AUDIO
RECEIVER
AUDIO
BACK END
SIGNAL
SECTION
SQUELCH FILTER
(ZERO IF)
(ASFIC)
FIRST RECEIVER
LOCAL OSCILLATOR,
2.1 MHz
REFERENCE OSCILLATOR
TRANSMITTER POWER AMPLIFIER SECTION
TRANSMIT
RF SIGNAL
RF POWER
AMPLIFIER
FEEDBACK
CONTROL
SB9600
DATA BUS
OPERATOR
DISPLAY DATA
TO TRANSCEIVER BOARD AND
CONTROL HEAD CIRCUITS
RECEIVER
AUDIO
RECEIVER
AUDIO
POWER
AMPLIFIER
AUDIO PA
ENABLE
RECEIVE RF SIGNAL
ANTENNA
SWITCH
P/O CONTROLLER
SECTION (NOTE 1)
MEMORY
CENTRAL
PROCESSOR
UNIT (CPU)
SUPPORT
LOGIC
(SLIC)
DISPLAY
NOTES:
1. REFER TO VOLUME 1 OF THIS
SERVICE MANUAL FOR INFORMATION
ABOUT CONTROLLER SECTION
2. REFER TO VOLUME 1 OF THIS
SERVICE MANUAL FOR INFORMATION
ABOUT CONTROL HEAD
Theory of Operation
LOUDSPEAKER
SQUELCH
DETECT
ANTENNA
SERIAL
PERIPHERAL
INTERFACE
(SPI) BUS
AUDIO PA
ENABLE
MAEPF-25078-A
7