Tait TP9100 - Page 184

184 Frequency Synthesizer Fault Finding TP9100 Service Manual
© Tait Electronics Limited May 2005
Figure 9.10 Measurement points for the VCO and related circuitry in UHF radios
+5V DEC
PIN 4 OF
IC506
PIN 4 OF
IC506
PIN 3 OF
Q506
PIN 3 OF
Q506
Q508 AND
R593
Q508 AND
R593
PIN 6 OF
Q506
PIN 6 OF
Q506
COLLECTOR
OF Q514
COLLECTOR
OF Q514
TX PORT
RX PORT
SIGNAL TYPES
RF ANALOG CLOCK DIGITAL
PLL
LOOP
FILTER
AND
SUMMER
FILTERING
OF SUPPLY
FOR VCO
CIRCUITRY
FREQUENCY SYNTHESIZER
PLL FEEDBACK
LOOP VOLTAGE
RECEIVE VCO
TRANSMIT VCO
TRANSMIT
BUFFER
AMPLIFIER
AND
COUPLER
5 V SWITCH
TR SWITCH
SYN TX LO
SYN RX LO1
TRANS- MITTER
RECEIVER
DIGITAL
CIRCUITRY
DIG SYN TR SW DIG SYN EN
+14 V
INVERTER
RECEIVE
BUFFER
AMPLIFIER
AND
COUPLER
JUNCTION OF
C541 AND R547
JUNCTION OF
C541 AND R547
R577
R544
+3V0 AN
L506
3V
SUPPLY
R593
R585