Motorola GM328 Service Manual page 531

UHF (450-520 MHz) Frequency Synthesis
DATA (U0101 PIN 100)
CLOCK (U0101 PIN 1)
CSX (U0101 PIN 2)
MOD IN (U0221 PIN 40)
+5V (U4211 PIN 1)
5, 20, 34, 36
+5V (U4211 PIN 1)
REFERENCE
OSCILLATOR
VOLTAGE
MULTIPLIER
Output LOCK (U5201-4) provides information about the lock status of the synthesizer loop. A high
level at this output indicates a stable loop. IC U5201 provides the 16.8 MHz reference frequency at
pin 19.
The serial interface (SRL) is connected to the µP via data line DATA (U5201-7), clock line CLK
(U5201-8), and chip enable line CSX (U5201-9).
7
DATA
8
CLK
9
CEX
10
MODIN
13, 30
VCC, DC5V
VDD, DC5V
23
XTAL1 U5201
LOW VOLTAGE
24
XTAL2
FRACTIONAL-N
25
SYNTHESIZER
WARP
32
PREIN
47
VCP
VMULT2 VMULT1
14
15
PRESCALER IN
Figure 2-3 UHF Synthesizer Block Diagram
4
LOCK
19
FREFOUT
6, 22, 33, 44
GND
43
IOUT
45
IADAPT
41
MODOUT
3
AUX4
1 (NU)
AUX2
TRB
2
AUX3
FILTERED 5V
28
SFOUT
BIAS1
40
BIAS2
AUX1
39
48
BWSELECT
LOCK (U0101 PIN 56)
FREF (U0221 PIN 34)
STEERING
LINE
2-POLE
LOOP
FILTER
VCO Bias
LO RF INJECTION
VOLTAGE
CONTROLLED
OSCILLATOR
TX RF INJECTION
(1ST STAGE OF PA)
To IF
Section
2-7