Figure 3-1. Prescaler Ic Block Diagram; Figure 3-2. Synthesizer Ic Block Diagram - Motorola ASTRO Digital Spectra Plus Service Manual

3-2
7
8
9
10
11
12
13
14
15
16
17
10
11
12
13
14
15
16
17
October 28, 2002
6 5 4 3 2
NC NC
PNP BASE
AUX
B+ PNP
IN BASE
5V OUT
AUX
5V
5V
GND
REG
REG
S.F. VIN
S
U
S.F. BASE
P
E
R
2ND L.O. CHARGE - PUMP
S.F. OUT
PHASE DETECTOR
F
I
L
S.F. CAP
T
E
R
S.F. GND
NC
DATA OUT
REF 8
NC
8 8 8 8
OUT BIAS VREF IN
18 19 20 21 22

Figure 3-1. Prescaler IC Block Diagram

6 5 4 3
S1
7
S2
8
ADAPTIVE FILTER
(300KHz)
EN3
9
SYNTHESIZER
ENR
CLOCK
DATA
RAMP CONTROL
SAMPLE LOGIC
SEL
DIG GND
DIVIDER
NC
REF
PRESCALER
DIV
CONTROL
REF IN
STEER
BUF
(LOCK)
REF
18 19 20 21 22

Figure 3-2. Synthesizer IC Block Diagram

1 44 43 42 41
PRE PRE BC1 BC2 MOD
IN VREF CONT
AUX
5V
MULTI - MODULUS
OUT
PRESCALER
u
P
U601
MOSAIC
I
PRESCALER
N
T
E
R
300KHz
F
A
C
E
S
R
2ND L.O. N
L
0 DET REF IN
2ND L.O. VCO (NOT USED)
VCO VCO VCO VCO VCO VCO
VCC BIAS GND BYP. TANK OUT NC
23 24 25 26 27
MAEPF-25181-O
2 1 44 43 42 41
OUTPUT
BUFFER
U602
CMOS
PHASE
MODULATOR
3 /
STEERING, &
+1
RAMP
BUF
3/
LOOP
&
AUX CONTROL
BIT LATCHES
23 24 25 26 27
MAEPF-25182-O
Theory of Operation: RF Board
40
PRE
OUT
VCC
39
BS
38
LATCH
37
CE
36
NC 35
GND
34
DATA
33
CLOCK
32
31
0 DET OUT
30
N OUT
29
28
40
LIN
GND
LIN
39
GND
BUF
38
BIAS
LIN VDD
37
RAMP
36
VDD
RAMP
35
RES
RAMP PNP
34
BASE
RAMP
CAP 33
GB
32
31
RAMP GB
DIG
30
VDD
0 MOD
29
RAMP
28
6881076C25-D