CIRCUIT DESCRIPTION
3-13
February 2001
Part No. 001-9800-001
Figure 3-4 RF Block Diagram (UHF Models)
Two-Pole
Bandpass Filter
Two-Pole
Bandpass Filter
45 MHz F
our Pole
Crystal Filter
L200/L201
L204/L206
Z204
RF Amp
Mixer
Q201
Q202
Second Mix
er/Detector
U201
Tripler
Q207
Z205
450 kHz
Ceramic Filter
Q205/
Q206
Switch/Inverter
14.850 MHz
44.550
MHz
Frequency
Control
Frequency
Control
Frequency
Control
Rx A
udio
To Audio/Logic Bd
RSSITo
Audio/Logic Bd
Q801
Module
U806
14.850 MHz
TCXO
Ref
erence
Divider
Main
Divider
Prescaler
Control
64/65
Prescaler
Phase
Detector
Tx Modulation
Tx A
udio/Data
Shift Register
U800
VCO Control
VCO
Buffer Amplifier
Q506
Q507
Q508
Q509Q600
Q601
Q504/
Q505
First
Amplifier
Second
Amplifier
Third
Amplifier
Predriver
8VTransmit
Switch
Dr
iver
Final
Antenna
Switch
Directional
Coupler
Harmonic
Filter
CR601,
CR603
Balance Adj
U802C
Summing Amp
Level Adjust
U802A
U802B
WB
Data
Tx
Data
Tx
Audio
U803
U804
Battery
Forward
Po
wer
Current
Sense
Power
Adj
U801
Channel
Programming
Control F
rom
Audio/Logic Bd
Power Amplifier Board
Power Control
Exciter
Synthesiz
er
Power
Amplifier
Receiver
Pin
Shift
Tx Freq
Rx Freq - 45 MHz
Synthesiz
er IC
Tx Modulation
Rx Freq - 45 MHz
Antenna
Lock
Detect
U802D
Charge
Current
Adjust
Q204
Injection
Amplifier
Q2
Q3
Q4
Q0
Q1
fR
fV
R821
Delayed
Transmit
From A/L Bd
Z206
450 kHz
Ceramic Filters
Z202
WB
NB
Switching
Q512
(470-512 MHz)
Q511
(470-512 MHz)
Q510
(470-512 MHz)
Q509
(470-512 MHz)
UHF SYNTHESIZER DESCRIPTION