UHF (403-470 MHz) Frequency Synthesis
2-7
4.2
Fractional-N Synthesizer
The LVFRAC-N synthesizer IC (U4201) consists of a pre-scaler, a programmable loop divider,
control divider logic, a phase detector, a charge pump, an A/D converter for low frequency digital
modulation, a balance attenuator to balance the high frequency analogue modulation and low
frequency digital modulation, a 13V positive voltage multiplier, a serial interface for control, and
finally a super filter for the regulated 5 volts.
Figure 2-3 UHF Synthesizer Block Diagram
A voltage of 5V applied to the super filter input (U4201 pin 30) supplies an output voltage of 4.5
VDC(VSF) at pin 28. It supplies the VCO, VCO modulation bias circuit (via R4322) and the
synthesizer charge pump resistor network (R4251, R4252). The synthesizer supply voltage is
provided by the 5V regulator U4211.
In order to generate a high voltage to supply the phase detector (charge pump) output stage at
pin 47 VCP (U4201-47), a voltage of 13 VDC is being generated by the positive voltage multiplier
circuitry (D4201, C4202, C4203). This voltage multiplier is basically a diode capacitor network driven
by two (1.05MHz) 180 degrees out of phase signals (U4201-14 and -15).
Output LOCK (U4201-4) provides information about the lock status of the synthesizer loop. A high
level at this output indicates a stable loop. IC U4201 provides the 16.8 MHz reference frequency at
pin 19.
The serial interface (SRL) is connected to the microprocessor via the data line DATA (U4201-7),
clock line CLK (U4201-8), and chip enable line CSX (U4201-9).
DATA
CLK
CEX
MODIN
VCC, DC5V
XTAL1
XTAL2
WARP
PREIN
VCP
REFERENCE
OSCILLATOR
VOLTAGE
MULTIPLIER
DATA (U0101 PIN 100)
CLOCK (U0101 PIN 1)
CSX (U0101 PIN 2)
MOD IN (U0221 PIN 40)
+5V (U4211 PIN 1)
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, 33, 44
43
45
3
2
28
14
15
40
FILTERED 5V
STEERING
LOCK (U0101 PIN 56)
PRESCALER IN
FREF (U0221 PIN 34)
39
BIAS2
41
48
5, 20, 34, 36
+5V (U4211 PIN 1)
AUX1
VDD, DC5V
MODOUT
U4201
LOW VOLTAGE
FRACTIONAL-N
SYNTHESIZER
AUX2
1 (NU)
BWSELECT
VCO Bias
TRB
To IF
Section
TX RF INJECTION
(1ST STAGE OF PA)
LO RF INJECTION
VOLTAGE
CONTROLLED
OSCILLATOR
LINE
2-POLE
LOOP
FILTER
Содержание GM338
Страница 1: ...GM328 GM338 GM398 Mobile Radios Detailed Service Manual 6804112J18 E December 2003 ...
Страница 4: ...THIS PAGE INTENTIONALLY LEFT BLANK ...
Страница 6: ...THIS PAGE INTENTIONALLY LEFT BLANK ...
Страница 7: ...GM328 GM338 GM398 Mobile Radios Service Maintainability Issue December 2003 ...
Страница 14: ...vi THIS PAGE INTENTIONALLY LEFT BLANK ...
Страница 16: ...viii THIS PAGE INTENTIONALLY LEFT BLANK ...
Страница 20: ...1 4 Radio Model Information THIS PAGE INTENTIONALLY LEFT BLANK ...
Страница 32: ...2 12 Notes For All Schematics and Circuit Boards THIS PAGE INTENTIONALLY LEFT BLANK ...
Страница 35: ...GM328 GM338 GM398 Mobile Radios Controlhead Service Information Issue December 2003 ...
Страница 42: ...1 4 GM398 Model GCN6115_ THIS PAGE INTENTIONALLY LEFT BLANK ...
Страница 56: ...2 14 Controlhead Model for GM398 THIS PAGE INTENTIONALLY LEFT BLANK ...
Страница 70: ...4 2 Allocation of Schematics and Circuit Boards THIS PAGE INTENTIONALLY LEFT BLANK ...
Страница 88: ...4 20 Controlhead GM398 PCB 8486178B03 Schematics THIS PAGE INTENTIONALLY LEFT BLANK ...
Страница 89: ...GM328 GM338 GM398 Mobile Radios Controller Service Information Issue December 2003 ...
Страница 114: ...2 2 Controller Troubleshooting Chart THIS PAGE INTENTIONALLY LEFT BLANK ...
Страница 140: ...3 26 Controller T7 T9 Schematic Diagrams THIS PAGE INTENTIONALLY LEFT BLANK ...
Страница 141: ...GM328 GM338 GM398 Mobile Radios VHF 136 174MHz Service Information Issue December 2003 ...
Страница 148: ...1 4 Technical Specifications THIS PAGE INTENTIONALLY LEFT BLANK ...
Страница 158: ...2 10 VHF 136 174 MHz Frequency Synthesis THIS PAGE INTENTIONALLY LEFT BLANK ...
Страница 166: ...3 8 Troubleshooting Flow Chart for VCO THIS PAGE INTENTIONALLY LEFT BLANK ...
Страница 168: ...4 2 Allocation of Schematics and Circuit Boards THIS PAGE INTENTIONALLY LEFT BLANK ...
Страница 186: ...4 20 VHF 1 25W PCBs Schematics Parts Lists THIS PAGE INTENTIONALLY LEFT BLANK ...
Страница 187: ...GM328 GM338 GM398 Mobile Radios UHF 403 470MHz Service Information Issue December 2003 ...
Страница 204: ...2 10 UHF 403 470 MHz Frequency Synthesis THIS PAGE INTENTIONALLY LEFT BLANK ...
Страница 212: ...3 8 Troubleshooting Flow Chart for VCO THIS PAGE INTENTIONALLY LEFT BLANK ...
Страница 214: ...4 2 Allocation of Schematics and Circuit Boards THIS PAGE INTENTIONALLY LEFT BLANK ...
Страница 235: ...GM328 GM338 GM398 Mobile Radios UHF Band 2 450 527MHz Service Information Issue December 2003 ...
Страница 252: ...2 10 UHF 450 527 MHz Frequency Synthesis THIS PAGE INTENTIONALLY LEFT BLANK ...
Страница 260: ...3 8 Troubleshooting Flow Chart for VCO THIS PAGE INTENTIONALLY LEFT BLANK ...
Страница 262: ...4 2 Allocation of Schematics and Circuit Boards THIS PAGE INTENTIONALLY LEFT BLANK ...
Страница 274: ...4 14 UHF Band 2 1 25W PCBs Schematics Parts List THIS PAGE INTENTIONALLY LEFT BLANK ...
Страница 275: ...GM338 GM398 Mobile Radios Low Band Service Information Issue December 2003 ...
Страница 280: ...iv THIS PAGE INTENTIONALLY LEFT BLANK ...
Страница 284: ...1 4 Technical Specifications THIS PAGE INTENTIONALLY LEFT BLANK ...
Страница 300: ...3 6 Troubleshooting Flow Chart for VCO THIS PAGE INTENTIONALLY LEFT BLANK ...
Страница 378: ...4 78 Low Band PCBs Schematics Parts Lists THIS PAGE INTENTIONALLY LEFT BLANK ...
Страница 379: ...GM338 Mobile Radios VHF 45W Bipolar 136 174MHz Service Information Issue December 2003 ...
Страница 400: ...4 2 Allocation of Schematics and Circuit Boards THIS PAGE INTENTIONALLY LEFT BLANK ...
Страница 411: ...GM338 Mobile Radios UHF1 40W Bipolar 403 470MHz Service Information Issue December 2003 ...
Страница 426: ...2 10 Frequency Synthesis THIS PAGE INTENTIONALLY LEFT BLANK ...
Страница 432: ...3 6 Troubleshooting Flow Chart for VCO THIS PAGE INTENTIONALLY LEFT BLANK ...
Страница 434: ...4 2 Allocation of Schematics and Circuit Boards THIS PAGE INTENTIONALLY LEFT BLANK ...
Страница 446: ...4 14 UHF 25 40W PCB Schematics Parts List THIS PAGE INTENTIONALLY LEFT BLANK ...
Страница 447: ...GM338 Mobile Radios UHF2 40W Bipolar 450 520MHz Service Information Issue December 2003 ...
Страница 462: ...2 10 Frequency Synthesis THIS PAGE INTENTIONALLY LEFT BLANK ...
Страница 468: ...3 6 Troubleshooting Flow Chart for VCO THIS PAGE INTENTIONALLY LEFT BLANK ...
Страница 470: ...4 2 Allocation of Schematics and Circuit Boards THIS PAGE INTENTIONALLY LEFT BLANK ...
Страница 482: ...4 14 UHF Band 2 25 40W PCB Schematics Parts List THIS PAGE INTENTIONALLY LEFT BLANK ...
Страница 483: ...GM338 Mobile Radio UHF B1 HIGH POWER LDMOS 403 470MHz Service Information Issue December 2003 ...
Страница 498: ...2 10 UHF 403 470 MHz Frequency Synthesis THIS PAGE INTENTIONALLY LEFT BLANK ...
Страница 506: ...4 2 Allocation of Schematics and Circuit Boards THIS PAGE INTENTIONALLY LEFT BLANK ...
Страница 518: ...4 14 UHF 25 40W PCB Schematics Parts List THIS PAGE INTENTIONALLY LEFT BLANK ...
Страница 519: ...GM338 Mobile Radios UHF B2 HIGH POWER LDMOS 450 520 MHz Service Information Issue December 2003 ...
Страница 534: ...2 10 UHF 450 520 MHz Frequency Synthesis THIS PAGE INTENTIONALLY LEFT BLANK ...
Страница 540: ...3 6 Troubleshooting Flow Chart for VCO THIS PAGE INTENTIONALLY LEFT BLANK ...
Страница 542: ...4 2 Allocation of Schematics and Circuit Boards THIS PAGE INTENTIONALLY LEFT BLANK ...
Страница 554: ...4 14 UHF Band 2 25 40W PCB Schematics Parts List THIS PAGE INTENTIONALLY LEFT BLANK ...