Table of Contents
5C.3-ii
Theory of Operation
Paragraph
Page
4.4
TX Secure Audio (optional) ....................................................................... 11
5.0
Transmit Signalling Circuits ................................................................... 12
5.1
Sub-audible Data (PL/DPL) ....................................................................... 12
5.2
High Speed Data ....................................................................................... 13
5.3
Dual Tone Multiple Frequency (DTMF) Data............................................. 13
6.0
Receive Audio Circuits............................................................................ 14
6.1
Squelch Detect .......................................................................................... 14
6.2
Audio Processing and Digital Volume Control ........................................... 15
6.3
Audio Amplification Speaker (+) Speaker (-) ............................................. 15
6.4
Handset Audio ........................................................................................... 16
6.5
Filtered Audio ............................................................................................ 16
6.6
RX Secure Audio (optional) ....................................................................... 16
7.0
Receive Signalling Circuits..................................................................... 17
7.1
Sub-audible Data Decoder (PL/DPL) ........................................................ 17
7.2
Alert Tone Circuits ..................................................................................... 17
Midband (66-88MHz) Specific Circuit Description
8.0
Receiver Front-End.................................................................................. 19
8.1
Front-End Band-Pass Filter & Pre-Amplifier .............................................. 19
8.2
Mixer and Intermediate Frequency (IF) Section ........................................ 19
8.3
IF IC (U2201) .............................................................................................. 20
9.0
Transmitter Power Amplifier (PA) 5-25W ............................................... 20
9.1
Power Controlled Stage............................................................................. 20
9.2
PA Stages.................................................................................................. 21
9.3
Directional Coupler .................................................................................... 21
9.4
Antenna Switch.......................................................................................... 21
9.5
Harmonic Filter .......................................................................................... 22
9.6
Power Control ............................................................................................ 22
10.0
Frequency Synthesis............................................................................... 23
10.1
Reference Oscillator .................................................................................. 23
10.2
Fractional-N Synthesizer (U2701) ............................................................. 23
10.3
Voltage Controlled Oscillator (VCO) .......................................................... 24
10.4
Synthesizer Operation ............................................................................... 24
Содержание GM950
Страница 2: ...Table of Contents 5 ii Band Specific Information ...
Страница 4: ...Table of Contents 5C ii 66 88MHz Specific Information ...
Страница 6: ...Table of Contents 5C 1 ii Model Chart and Test Specifications ...
Страница 12: ...Table of Contents 5C 2 ii Radio Tuning Procedure ...
Страница 22: ...Midband 66 88MHz Tuning Procedure 5C 2 10 Radio Tuning Procedure ...
Страница 50: ...Frequency Synthesis 5C 3 26 Theory of Operation ...