1-10
THEORY OF OPERATION
6.0
UHF Receiver (Models with PCB 8486458Z03)
The UHF receiver consists of a front end, back end, and automatic gain control circuits. A block
diagram of the receiver is shown in Figure 2-3. Detailed descriptions of these features are contained
in the paragraphs that follow.
Figure 1-5
UHF Receiver Block Diagram.
6.1
Receiver Front-End
(
Refer to Figure 2-3 and the UHF Receiver Front End schematic diagram for PCB 8486458Z03)
The RF signal is received by the antenna and applied to a low-pass filter. For UHF, the filter consists
of L101, L102, C102, C103, C104. The filtered RF signal is passed through the antenna switch. The
antenna switch circuit consists of two PIN diodes(CR101 and CR102) and a pi network (C106, L104
and C107).The signal is then applied to a varactor tuned bandpass filter. The UHF bandpass filter
comprises of L301, L302, C302, C303, C304, CR301 and CR302. The bandpass filter is tuned by
applying a control voltage to the varactor diodes(CR301 and CR302) in the filter.
The bandpass filter is electronically tuned by the DACRx from IC404 which is controlled by the
microprocessor. Depending on the carrier frequency, the DACRx will supply the tuned voltage to the
varactor diodes in the filter. Wideband operation of the filter is achieved by shifting the bandpass
filter across the band.
Crystal
Filter
Mixer
Varactor
Tuned Filter
RF Amp
Varactor
Tuned Filter
Pin Diode
Antenna
Switch
RF Jack
Antenna
Control Voltage
from ASFIC
First LO
from VCO
Second LO
IF Amp
455kHz
Filter
Switch
455kHz
Filter
455kHz
Filter
Switch
Demodulator
RSSI
Limiter
Recovered Audio
BW SEL
U301
Содержание GP series
Страница 1: ...Professional Portable Radio Detailed Service Manual 6866558D03 P ...
Страница 2: ...ii ...
Страница 5: ...Professional Radio GP Series Service Maintainability Issue July 2007 ...
Страница 14: ...x THIS PAGE INTENTIONALLY LEFT BLANK ...
Страница 16: ...xii THIS PAGE INTENTIONALLY LEFT BLANK ...
Страница 26: ...2 6 MAINTENANCE THIS PAGE INTENTIONALLY LEFT BLANK ...
Страница 32: ...4 2 Error Codes Notes ...
Страница 33: ...Professional Radio GP Series Keypad and Flex Service Information Issue July 2007 ...
Страница 36: ...iv THIS PAGE INTENTIONALLY LEFT BLANK ...
Страница 40: ...1 4 THEORY OF OPERATION THIS PAGE INTENTIONALLY LEFT BLANK ...
Страница 48: ...2 8 PCB Schematic Diagrams and Parts List Flexes THIS PAGE INTENTIONALLY LEFT BLANK ...
Страница 52: ...2 12 PCB Schematic Diagrams and Parts List Keypad THIS PAGE INTENTIONALLY LEFT BLANK ...
Страница 56: ...2 16 PCB Schematic Diagrams and Parts List Keypad THIS PAGE INTENTIONALLY LEFT BLANK ...
Страница 59: ...Professional Radio GP Series Power Distribution and Controller Service Information Issue July 2007 ...
Страница 62: ...iv THIS PAGE INTENTIONALLY LEFT BLANK ...
Страница 72: ...3 4 CONTROLLER SCHEMATICS THIS PAGE INTENTIONALLY LEFT BLANK ...
Страница 92: ...3 24 Controller Set 3 PCB 8486458Z03 UHF 8486686Z02 UHF2 THIS PAGE INTENTIONALLY LEFT BLANK ...
Страница 98: ...3 30 Controller Set 4 PCB 8416256H02 UHF Controller Audio Power Amplifier Schematic Diagram ...
Страница 100: ...3 32 Controller Set 5 PCB 8486743Z02 UHF Intentionally left blank Controller ASFIC ON_OFF Schematic Diagram ...
Страница 101: ...Controller Set 5 PCB 8486743Z02 UHF 3 33 Controller Micro Processor Schematic Diagram ...
Страница 102: ...3 34 Controller Set 5 PCB 8486743Z02 UHF Controller Interface Schematic Diagram ...
Страница 103: ...Controller Set 5 PCB 8486743Z02 UHF 3 35 Controller Audio Power Amplifier Schematic Diagram ...
Страница 104: ...3 36 Controller Set 5 PCB 8486743Z02 UHF THIS PAGE INTENTIONALLY LEFT BLANK ...
Страница 108: ...3 40 Controller Schematics Set 6 PCB 8415234H05 Narrow Band THIS PAGE INTENTIONALLY LEFT BLANK ...
Страница 109: ...Professional Radio GP Series UHF 403 470MHz Narrow Band 450 470MHz Service Information Issue July 2007 ...
Страница 134: ...1 22 THEORY OF OPERATION THIS PAGE INTENTIONALLY LEFT BLANK ...
Страница 150: ...3 6 UHF PCB SCHEMATICS PARTS LISTS THIS PAGE INTENTIONALLY LEFT BLANK ...
Страница 160: ...3 16 UHF PCB 8480450Z03 Schematics THIS PAGE INTENTIONALLY LEFT BLANK ...
Страница 178: ...3 34 UHF PCB 8480587Z03 Schematics THIS PAGE INTENTIONALLY LEFT BLANK ...
Страница 182: ...3 38 UHF PCB 8480587Z03 Parts List THIS PAGE INTENTIONALLY LEFT BLANK ...
Страница 190: ...3 46 UHF PCB 8480587Z05 Parts List THIS PAGE INTENTIONALLY LEFT BLANK ...
Страница 200: ...3 56 UHF PCB 8480450Z13 14 Schematics THIS PAGE INTENTIONALLY LEFT BLANK ...
Страница 214: ...3 70 UHF PCB 8486458Z03 Schematics THIS PAGE INTENTIONALLY LEFT BLANK ...
Страница 228: ...3 84 UHF PCB 8415234H01 Schematics THIS PAGE INTENTIONALLY LEFT BLANK ...
Страница 244: ...3 100 UHF PCB 8415234H02 Schematics THIS PAGE INTENTIONALLY LEFT BLANK ...
Страница 250: ...3 106 UHF PCB 8415234H02 Parts List THIS PAGE INTENTIONALLY LEFT BLANK ...
Страница 260: ...3 116 Circuit Board Schematic Diagrams and Parts List PCB No 8415234H05 THIS PAGE INTENTIONALLY LEFT BLANK ...
Страница 270: ...3 126 UHF PCB 8415234H05 EPP Parts List THIS PAGE INTENTIONALLY LEFT BLANK ...
Страница 280: ...3 136 UHF PCB 8415234H08 Schematics THIS PAGE INTENTIONALLY LEFT BLANK ...
Страница 290: ...3 146 UHF PCB 8415234H08 Parts List THIS PAGE INTENTIONALLY LEFT BLANK ...
Страница 293: ...UHF PCB 8486743Z02 Schematics 3 149 UHF 403 470 MHz Receiver Front End Schematic Diagram ...
Страница 294: ...3 150 UHF PCB 8486743Z02 Schematics UHF 403 470 MHz Receiver Back End Schematic Diagram ...
Страница 295: ...UHF PCB 8486743Z02 Schematics 3 151 UHF 403 470 MHz Synthesizer Schematic Diagram ...
Страница 296: ...3 152 UHF PCB 8486743Z02 Schematics UHF 403 470 MHz Voltage Controlled Oscillator Schematic Diagram ...
Страница 297: ...UHF PCB 8486743Z02 Schematics 3 153 UHF 403 470 MHz Transmitter Schematic Diagram ...
Страница 298: ...3 154 UHF PCB 8486743Z02 Schematics THIS PAGE INTENTIONALLY LEFT BLANK ...
Страница 316: ...3 172 UHF PCB 8415234H05 450 470 MHz Narrow Band THIS PAGE INTENTIONALLY LEFT BLANK ...
Страница 325: ...Professional Radio GP Series UHF2 450 527MHz Service Information Issue July 2007 ...
Страница 342: ...1 14 THEORY OF OPERATION THIS PAGE INTENTIONALLY LEFT BLANK ...
Страница 352: ...2 10 TROUBLESHOOTING CHARTS THIS PAGE INTENTIONALLY LEFT BLANK ...
Страница 356: ...3 4 UHF2 PCB SCHEMATICS PARTS LISTS THIS PAGE INTENTIONALLY LEFT BLANK ...
Страница 384: ...3 32 UHF2 PCB 8485677Z02 GP1280 Schematics THIS PAGE INTENTIONALLY LEFT BLANK ...
Страница 386: ...3 34 Voice Storage Parts List GP1280 THIS PAGE INTENTIONALLY LEFT BLANK ...
Страница 394: ...3 42 UHF2 PCB 8485677Z03 GP1280 Parts List THIS PAGE INTENTIONALLY LEFT BLANK ...
Страница 404: ...3 52 UHF2 PCB 8486686Z02 Schematics THIS PAGE INTENTIONALLY LEFT BLANK ...
Страница 441: ...Professional Radio GP Series 800 MHz 806 870MHz Service Information Issue July 2007 ...
Страница 444: ...iv THIS PAGE INTENTIONALLY LEFT BLANK ...
Страница 456: ...1 12 THEORY OF OPERATION THIS PAGE INTENTIONALLY LEFT BLANK ...
Страница 464: ...3 2 800MHz PCB schematics Parts list THIS PAGE INTENTIONALLY LEFT BLANK ...