Tait T860 Series II, Service Manual

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M860-00-Preliminary
T865 Circuit Operation B2.1
Copyright TEL 30/06/98
2 T865 Circuit Operation
This section provides a basic description of the circuit operation of the T865 receiver.
Note: Unless otherwise specified, the term "PGM800Win" used in this and follow-
ing sections refers to version 2.00 and later of the software.
Refer to Section 6 where the parts lists, grid reference index and diagrams will provide
detailed information on identifying and locating components and test points on the
main PCB. The parts list and diagrams for the VCO PCB are in Part E.
The following topics are covered in this section.
Section Title Page
2.1 Introduction 2.3
2.2 Receiver Front End 2.4
2.3 Mixer 2.5
2.4 IF Circuitry 2.5
2.5 Noise Mute (Squelch) 2.6
2.6 Carrier Mute 2.6
2.7 Audio Processor 2.7
2.8 Power Supply And Regulators 2.8
2.9 Microcontroller 2.9
2.10 Synthesised Local Oscillator 2.10
2.11 VCO 2.11
2.12 Received Signal Strength Indicator (RSSI) 2.11
Figure Title Page
2.1
2.2
2.3
2.4
2.5
2.6
T865 High Level Block Diagram
T865 Front End, IF and Mute Block Diagram
T865 Audio Processor Block Diagram
T865 Power Supply And Regulator Block Diagram
T865 Microcontroller Block Diagram
T865 Synthesiser Block Diagram
2.3
2.4
2.7
2.8
2.9
2.10