Motorola ASTRO Digital Spectra Service Manual

vi Table of Contents
October 28, 2002 6881076C25-D
3.5.2.9 Doubler...................................................................................................................3-50
3.5.2.10 Synthesizer Feedback............................................................................................3-50
3.5.2.11 Second Buffer.........................................................................................................3-50
3.5.2.12 Receive/Transmit Switch........................................................................................3-50
3.5.3 800 MHz Band.................................................................................................................3-50
3.5.3.1 General...................................................................................................................3-50
3.5.3.2 Super Filter 8.6 V ...................................................................................................3-50
3.5.3.3 VCO........................................................................................................................3-50
3.5.3.4 Receive Mode-AUX 1* and AUX 2* High ...............................................................3-51
3.5.3.5 Transmit Mode-AUX 1* High; AUX 2* Low.............................................................3-51
3.5.3.6 TalkAround Mode-AUX 1* Low; AUX 2* Low.........................................................3-51
3.5.3.7 VCO Buffer.............................................................................................................3-51
3.5.3.8 First Buffer Circuit...................................................................................................3-51
3.5.3.9 Doubler...................................................................................................................3-51
3.5.3.10 Second Buffer.........................................................................................................3-52
3.5.3.11 K9.4 V Switch.........................................................................................................3-52
3.6 Receiver Front-End ......................................................................................................................3-53
3.6.1 VHF Band........................................................................................................................3-53
3.6.1.1 General...................................................................................................................3-53
3.6.1.2 Theory of Operation ...............................................................................................3-53
3.6.2 UHF Band........................................................................................................................3-53
3.6.2.1 General...................................................................................................................3-53
3.6.2.2 Theory of Operation ...............................................................................................3-54
3.6.3 800 MHz Band.................................................................................................................3-54
3.6.3.1 General...................................................................................................................3-54
3.6.3.2 Theory of Operation ...............................................................................................3-54
3.7 Power Amplifiers ..........................................................................................................................3-55
3.7.1 VHF Band Power Amplifiers............................................................................................3-55
3.7.1.1 High-Power Amplifier..............................................................................................3-55
3.7.1.1.1 Transmitter......................................................................................................3-55
3.7.1.1.2 Antenna Switch and Harmonic Filter...............................................................3-56
3.7.1.1.3 Power Control Circuitry ...................................................................................3-57
3.7.1.2 25/10-Watt Power Amplifier....................................................................................3-59
3.7.1.2.1 Antenna Switch and Harmonic Filter...............................................................3-60
3.7.1.2.2 Power Control Circuitry ...................................................................................3-60
3.7.1.3 50-Watt Power Amplifiers.......................................................................................3-63
3.7.1.3.1 Transmitter......................................................................................................3-63
3.7.1.3.2 Antenna Switch and Harmonic Filter...............................................................3-64
3.7.1.3.3 Power Control Circuitry ...................................................................................3-65
3.7.2 UHF Band Power Amplifiers............................................................................................3-68
3.7.2.1 High-Power Amplifier..............................................................................................3-68
3.7.2.1.1 Transmitter......................................................................................................3-68
3.7.2.1.2 Antenna Switch and Harmonic Filter...............................................................3-69
3.7.2.1.3 Power Control Circuitry ...................................................................................3-69
3.7.2.2 40-Watt Power Amplifier.........................................................................................3-72
3.7.2.2.1 Transmitter......................................................................................................3-72
3.7.2.2.2 Antenna Switch and Harmonic Filter...............................................................3-73
3.7.2.2.3 Power Control Circuitry ...................................................................................3-74
3.7.3 800 MHz Band Power Amplifiers.....................................................................................3-77
3.7.3.1 15- and 35-Watt Amplifiers.....................................................................................3-77
3.7.3.1.1 Transmitter......................................................................................................3-77
3.7.3.1.2 Antenna Switch and Harmonic Filter...............................................................3-78
3.7.3.1.3 Power Control Circuitry ...................................................................................3-79
3.7.3.1.4 Temperature Sensing......................................................................................3-81

Motorola ASTRO Digital Spectra Specifications

General

Brand	Motorola
Model	ASTRO Digital Spectra
Category	Radio
Language	English