T855 Circuit Operation
B2.3
Copyright TEL
2.1
Introduction
Figure 2.1 T855 High Level Block Diagram
The T855 receiver consists of a number of distinct stages:
• front end
• mixer
• synthesised local oscillator
• IF
• audio processor
• mute (squelch)
• regulator circuits
• received signal strength indicator (RSSI).
These stages are clearly identifiable in Figure 2.1. Refer to the circuit diagrams in Sec-
tion 6 for further detail.
45MHz
IF
455kHz
IF
Carrier
Mute
RSSI
Noise
Mute
Front
End
12.8MHz
Master
Oscillator
Audio
Processor
Mixer
Mixer
Limiter
FM
Detector
Synthesised
Local
Oscillator
Second
Local
Oscillator
Speaker
}
600
Ω
Line
Summary of Contents for T850 II Series
Page 12: ...12 M850 00 31 09 98 Copyright TEL...
Page 14: ...AII M850 00 31 09 98 Copyright TEL...
Page 20: ...A2 4 Mechanical M850 00 31 09 98 Copyright TEL...
Page 26: ...BII M850 00 31 09 98 Copyright TEL...
Page 28: ...B1 2 T855 General Information M850 00 31 09 98 Copyright TEL...
Page 40: ...B1 14 T855 General Information M850 00 31 09 98 Copyright TEL...
Page 42: ...B2 2 T855 Circuit Operation M850 00 31 09 98 Copyright TEL...
Page 68: ...B4 2 T855 Functional Testing M850 00 31 09 98 Copyright TEL...
Page 74: ...B4 8 T855 Functional Testing M850 00 31 09 98 Copyright TEL...
Page 94: ...B5 20 T855 Fault Finding M850 00 31 09 98 Copyright TEL...
Page 96: ...B6 1 2 T855 PCB Information M850 00 31 09 98 Copyright TEL...
Page 102: ...B6 2 2 T800 04 0000 RSSI PCB Information M850 00 31 09 98 Copyright TEL...
Page 108: ...B6 3 2 T855 PCB Information M850 00 31 09 98 Copyright TEL...
Page 115: ...IPN 220 01396 02 M850 00 T855 PCB Information B6 3 9 Copyright TEL 31 09 98...
Page 122: ...IPN 220 01396 02 B6 3 16 T855 PCB Information M850 00 31 09 98 Copyright TEL...
Page 124: ...CII M850 00 31 09 98 Copyright TEL...
Page 126: ...C1 2 T856 857 General Information M850 00 31 09 98 Copyright TEL...
Page 140: ...C1 16 T856 857 General Information M850 00 31 09 98 Copyright TEL...
Page 154: ...C2 14 T856 857 Circuit Operation M850 00 31 09 98 Copyright TEL...
Page 170: ...C4 2 T856 857 Functional Testing M850 00 31 09 98 Copyright TEL...
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Page 198: ...C6 1 2 T856 857 PCB Information M850 00 31 09 98 Copyright TEL...
Page 204: ...C6 2 2 T856 PCB Information M850 00 31 09 98 Copyright TEL...
Page 220: ...C6 3 2 T857 PCB Information M850 00 31 09 98 Copyright TEL...
Page 232: ...IPN 220 01398 02 C6 3 14 T857 PCB Information M850 00 31 09 98 Copyright TEL...
Page 234: ...DII M850 00 31 09 98 Copyright TEL...
Page 236: ...D1 2 T858 859 General Information M850 00 31 09 98 Copyright TEL...
Page 248: ...D2 2 T858 859 Circuit Operation M850 00 31 09 98 Copyright TEL...
Page 256: ...D3 2 T858 859 Initial Adjustment M850 00 31 09 98 Copyright TEL...
Page 264: ...D3 10 T858 859 Initial Adjustment M850 00 31 09 98 Copyright TEL...
Page 266: ...D4 2 T858 859 Fault Finding M850 00 31 09 98 Copyright TEL...
Page 282: ...D5 1 2 T858 859 PCB Information M850 00 31 09 98 Copyright TEL...
Page 288: ...D5 2 2 T858 PCB Information M850 00 31 09 98 Copyright TEL...
Page 293: ...IPN 220 01141 01 M850 00 T858 PCB Information D5 2 7 Copyright TEL 31 09 98...
Page 298: ...IPN 220 01141 01 D5 2 12 T858 PCB Information M850 00 31 09 98 Copyright TEL...
Page 300: ...D5 3 2 T859 PCB Information M850 00 31 09 98 Copyright TEL...
Page 305: ...IPN 220 01159 01 M850 00 T859 PCB Information D5 3 7 Copyright TEL 31 09 98...
Page 312: ...EII M850 00 31 09 98 Copyright TEL...
Page 316: ...E2 2 T850 VCO PCB Information M850 00 31 09 98 Copyright TEL...
Page 328: ...G1 4 T855 Link Selectable Features M850 00 31 09 98 Copyright TEL...
Page 332: ...G2 4 T856 857 Optional Features M850 00 31 09 98 Copyright TEL...
Page 334: ...G3 2 Talk Through Repeater M850 00 31 09 98 Copyright TEL...
Page 340: ...HII M850 00 31 09 98 Copyright TEL...
Page 356: ...I II M850 00 31 09 98 Copyright TEL...
Page 358: ...I1 2 Tools Required M850 00 31 09 98 Copyright TEL...
Page 366: ...I2 8 T855 856 857 SII SI Conversion M850 00 31 09 98 Copyright TEL...
Page 370: ...I3 4 T858 859 SII SI Conversion M850 00 31 09 98 Copyright TEL...