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2-24
Theory of Operation
: VHF Synthesizer
Figure 2-16. Synthesizer Block Diagram
DATA
CLK
CEX
MODIN
VCC, DC5V
XTAL1
XTAL2
WARP
PREIN
VCP
REFERENCE
OSCILLATOR
VOLTAGE
MULTIPLIER
VOLTAGE
CONTROLLED
OSCILLATOR
2-POLE
LOOP
FILTER
DATA (U409 PIN 100)
CLOCK (U409 PIN 1)
CSX (U409 PIN 2)
MOD IN (U404 PIN 40)
+5V (U3711 PIN 4)
7
8
9
10
13, 30
23
24
25
32
47
VMULT2
VMULT1
BIAS1
SFOUT
AUX3
AUX4
IADAPT
IOUT
GND
FREFOUT
LOCK
4
19
6, 22, 23, 24
43
45
3
2
28
14
15
40
FILTERED 5V
STEERING
LINE
LOCK (U409 PIN 56)
PRESCALER IN
LO RF INJECTION
TX RF INJECTION
(1ST STAGE OF PA)
FREF (U3220 PIN 21 & U404 PIN 34)
39
BIAS2
41
DUAL
TSTRS
48
5V
R5
5, 20, 34, 36
(U3201 PIN 5)
AUX1
VDD, 3.3V
MODOUT
U3701
LOW VOLTAGE
FRACTIONAL-N
SYNTHESIZER
Summary of Contents for PR860
Page 1: ...PR860 Two Way Portable Radio Detailed Service Manual ...
Page 2: ......
Page 5: ...iv Notes ...
Page 9: ...viii Table of Contents Notes ...
Page 13: ...Notes xii List of Figures ...
Page 17: ...1 4 Introduction Radio Model Information Notes ...
Page 51: ...2 34 Theory of Operation Voltage Control Oscillators VCO Notes ...
Page 81: ...4 4 Schematic Diagrams Overlays and Parts Lists Flex Layout Notes ...
Page 193: ...4 116 Schematic Diagrams Overlays and Parts Lists Low Band Section Notes ...
Page 196: ......