Figure 10-5. Uhf Vco Block Diagram - Motorola CP150 Service Manual

465-495 MHz UHF Theory Of Operation: UHF Frequency Generation Circuitry
C267, and varactor D261. High-port audio modulation from the synthesizer IC is applied as
VCO_MOD to varactor D262 which modulates the transmit VCO.
NC
NC
V_SF (U201 Pin 28)
Steer Line
Voltage
(V_STEER)
RX RX VCO
Tank Circuit
TX TX VCO
Tank Circuit
6880309N62-C
TRB_IN
Pin 20
Pin 7
TX/RX/BS
Pin 13
Switching Network
Pin 3
Vcc-Superfilter
U251
VCOBIC
Collector/RF in
Pin 4
Pin 5 RX
Rx Active
Bias
Pin 6
Pin 16
TX
Tx Active
Bias
Pin 15
Vsens
Circuit
Pin 18 Pin 2
Rx-I adjust
Vcc-Logic
3V
(U330 Pin 5)

Figure 10-5. UHF VCO Block Diagram

AUX3 (U201 Pin 2)
Pin 19
Prescaler Out
Pin 12
Presc
Buffer
Q280
Pin 8
RX
Pin 14
VCC Buffers
Pin 10
TX
Pin 1 Pins 9,11,17
Tx-I adjust
V_SF
(U201 Pin 28)
10-7
U201 Pin 32
RX INJ
3V (U330 Pin 5)
Matching
TX INJ
Network
June, 2005