Motorola GTX - Page 30

2-2 68P02948C90-O February 1997
Theory of Operation GTX/GTX LTR/LTS 2000 Portable Radios Service Manual
Transmitter
ANTENNA
SWITCH
FRONT-END
MODULE
H FILTER
POWER
AMPLIFIER
935-941MHz
1ST MIXER
IF
45.1 MHz
2ND MIXER &
DEMODULATOR
DET_AUDIO
RX_INJ
POWER
CONTROL
PWR_REF
TX_INJ
16.8 MHz
REFERENCE
TEMPUS_D/A
PWR_REF
RED
YELLOW
5R
MIC_EN
SCB4
SCB3
SCB2
SCB1
D/A
DAC_SEL
LOCK_DET
SYNT_EN
2.1 MHz
MOD_IN
SPI_DATA
SPI_CLCK
PRE-
AMP
TXB+
889.9-995.9 MHz
RF & AUDIO SECTION
µPROCESSOR
HC11K1
SERIAL
EEPROM 4K
8-DIGIT
LCD DISPLAY
4 X 4 KEYPAD
DISPLAY/KEYBOARD DRIVER
ASFIC
PARALLEL BUS
SPI BUS
PTT
MONITOR
OPT
LOCK_DET
SYNT_EN
PEND_EN
SCI
ROT1
ROT2
VOL_SENSE
DAC_SEL
RAM 8K
ROM 128K
LOGIC SECTION
28-PIN
CONNECTOR
TO LOGIC SECTION
28-PIN
CONNECTOR
FROM RF SECTION
VOLUME
ROTARY
SWITCH
& LEVEL
CONTROL
ENCODER
VOL
ROT1
ROT2
RX_AUDIO
MUTE
INT. SPKR
ACC.
AUDIO
PA
896-902 MHz
CON.
MIC_IN
INT. MIC
ACC.
MIC.
PREAMP
CON.
OSCILLATOR
16.8 MHZ
HEAR CLEAR
RADIO FUNCTIONAL BLOCK DIAGRAM