DANIELS
ELECTRONICS LTD.
TM
VHF Enhanced Extra Wideband Receiver Instruction Manual IM10-VR3H040-AB
iii
TABLE OF CONTENTS
Page
1 GENERAL................................................................................................................. 1-1
1.1 Introduction........................................................................................................ 1-1
1.2 VR-3H040 Extra Wideband Receiver Family Models ...................................... 1-1
1.3 Manual Organization ......................................................................................... 1-2
1.4 Performance Specifications ............................................................................... 1-3
1.4.1 General........................................................................................................... 1-3
1.4.2 Enhanced Front End Performance Specifications ......................................... 1-5
1.4.3 Enhanced Synthesizer Performance Specifications....................................... 1-5
1.4.4 Physical
Specifications .................................................................................. 1-6
2 SYSTEM
OVERVIEW ............................................................................................. 2-1
2.1 Receiver Operation ............................................................................................ 2-1
2.2 Frequency Selection........................................................................................... 2-2
2.3 Receiver Assembly and Adjustment.................................................................. 2-3
2.3.1 Complete Receiver Alignment....................................................................... 2-3
2.3.2 Frequency
Change ......................................................................................... 2-4
2.3.3 Minor Frequency Change .............................................................................. 2-5
2.3.4 Major Frequency Change .............................................................................. 2-5
2.4 21.4 MHz IF/Audio Main Board ....................................................................... 2-6
2.5 Enhanced Front End .......................................................................................... 2-6
2.6 Enhanced Synthesizer........................................................................................ 2-7
2.7 Receiver Front Panel Illustration....................................................................... 2-8
2.8 MT-3 Receiver Case – Exploded View ............................................................. 2-9
2.9 VR-3H040 Family Enhanced Receiver Block Diagram.................................. 2-10
3
THEORY OF OPERATION ..................................................................................... 3-1
3.1 21.4 MHz IF / Audio Main Board ..................................................................... 3-1
3.1.1 General........................................................................................................... 3-1
3.1.2 Power
Supplies .............................................................................................. 3-1
3.1.3 IF Buffer Board.............................................................................................. 3-1
3.1.4 First IF Amplifier........................................................................................... 3-2
3.1.5 Second IF / Demodulation ............................................................................. 3-2
3.1.6 Received Signal Strength Indicator (RSSI) ................................................... 3-2
3.1.7 Audio
Processing ........................................................................................... 3-3
3.1.8 Post
Discriminator Filtering .......................................................................... 3-4
3.1.9 Squelch
Circuitry ........................................................................................... 3-5
3.1.10 COR Outputs.................................................................................................. 3-6
3.1.11 Channel Selection .......................................................................................... 3-7
3.2 Enhanced Front End .......................................................................................... 3-8
3.2.1 General........................................................................................................... 3-8
3.2.2 Power and Interconnection ............................................................................ 3-8
3.2.3 Preselector
Filter............................................................................................ 3-8
