Motorola ASTRO XTL 1500 Detailed Service Manual page 8

Table of Contents
3.9 Radio Power Distribution..............................................................................................................3-15
3.10 Receiver Front-End ......................................................................................................................3-16
3.10.1 VHF (136-174 MHz) Band ..............................................................................................3-16
3.10.1.1 15 dB Step Attenuator (U3250) ..............................................................................3-17
3.10.1.2 PIN Diode Switches................................................................................................3-17
3.10.1.3 Preselector Filters ..................................................................................................3-17
3.10.1.4 Low-Noise Amplifiers (Q3255, Q3252)...................................................................3-17
3.10.1.5 Mixer (D3258).........................................................................................................3-18
3.10.2 UHF Range 1 (380-470 MHz) Band ...............................................................................3-18
3.10.2.1 Highpass Filter and First Low-Noise Amplifier .......................................................3-19
3.10.2.2 Preselector Filter ....................................................................................................3-19
3.10.2.3 Switchable 15 dB Attenuator ..................................................................................3-19
3.10.2.4 Low-Noise Amplifier (LNA, U5302) ........................................................................3-19
3.10.2.5 Image Filter ............................................................................................................3-19
3.10.2.6 Mixer.......................................................................................................................3-19
3.10.3 UHF Range 2 (450-520 MHz) Band ...............................................................................3-20
3.10.3.1 Highpass Filter and First Low-Noise Amplifier .......................................................3-20
3.10.3.2 Preselector Filter ....................................................................................................3-21
3.10.3.3 Switchable 15 dB Attenuator ..................................................................................3-21
3.10.3.4 Low-Noise Amplifier (LNA, U5302) ........................................................................3-21
3.10.3.5 Image Filter ............................................................................................................3-21
3.10.3.6 Mixer.......................................................................................................................3-21
3.10.4 700-800 MHz Band.........................................................................................................3-22
3.10.4.1 Preselector Filters ..................................................................................................3-22
3.10.4.2 Low-Noise Amplifier (LNA, U6250) ........................................................................3-22
3.10.4.3 Mixer (U6251).........................................................................................................3-23
3.11 Receiver Back-End.......................................................................................................................3-23
3.11.1 VHF (136-174 MHz) Band ...............................................................................................3-23
3.11.1.1 Intermediate Frequency (IF) Section......................................................................3-23
3.11.1.2 ABACUS III IC ........................................................................................................3-23
3.11.2 UHF Range 1 (380-470 MHz) Band ................................................................................3-24
3.11.2.1 Intermediate Frequency (IF) Filter..........................................................................3-25
3.11.2.2 ABACUS III IC (U5002) ..........................................................................................3-25
3.11.3 UHF Range 2 (450-520 MHz) Band ................................................................................3-26
3.11.3.1 Intermediate Frequency (IF) Filter..........................................................................3-26
3.11.3.2 ABACUS III IC (U5002) ..........................................................................................3-26
3.11.4 700-800 MHz Band.........................................................................................................3-27
3.11.4.1 Intermediate Frequency (IF) Filter..........................................................................3-28
3.11.4.2 ABACUS III IC (U6000) ..........................................................................................3-28
3.12 Transmitter ...................................................................................................................................3-29
3.12.1 VHF (136-174 MHz) Band ...............................................................................................3-29
3.12.1.1 50-Watt Transmitter................................................................................................3-29
3.12.1.2 Output Network (ON)..............................................................................................3-30
3.12.1.3 Power Control.........................................................................................................3-31
3.12.2 UHF Range 1 (380-470 MHz) Band ................................................................................3-33
3.12.2.1 40-Watt Transmitter................................................................................................3-33
3.12.2.2 Output Network (ON)..............................................................................................3-34
3.12.2.3 Power Control.........................................................................................................3-35
3.12.3 UHF Range 2 (450-520 MHz) Band ................................................................................3-37
3.12.3.1 45-Watt Transmitter................................................................................................3-37
3.12.4 700-800 MHz Band.........................................................................................................3-41
3.12.4.1 35-Watt Transmitter................................................................................................3-41
3.13 Frequency Generation Unit (FGU) ...............................................................................................3-45
3.13.1 VHF (136-174 MHz) Band ...............................................................................................3-45
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June 15, 2005