Motorola Astro XTL 1500 - Page 7

vi Table of Contents
June 15, 2005 6815854H01-A
2.3.2.2 Voltage Regulators...................................................................................................2-2
2.3.3 User Interface (Keypad, STN Display, Volume and Frequency Knob) section .................2-2
2.3.3.1 Display......................................................................................................................2-2
2.3.3.2 Keypad, Volume and Frequency Knob.....................................................................2-3
2.3.3.3 Status LEDs .............................................................................................................2-3
2.3.3.4 Backlight LEDs .........................................................................................................2-3
2.3.4 Vehicle Interface Ports ......................................................................................................2-4
2.4 Receiver Section ............................................................................................................................2-5
2.4.1 VHF Band Radios..............................................................................................................2-5
2.4.1.1 Front-End Section ....................................................................................................2-5
2.4.1.2 Back-End Section.....................................................................................................2-5
2.4.2 UHF Range 1/UHF Range 2 Band Radios........................................................................2-5
2.4.2.1 Front-End Section ....................................................................................................2-5
2.4.2.2 Intermediate Frequency and Back-End....................................................................2-5
2.4.3 700–800 MHz Band Radios ..............................................................................................2-6
2.4.3.1 Front-End Section ....................................................................................................2-6
2.4.3.2 Back-End Section.....................................................................................................2-6
2.5 Transmitter Section ........................................................................................................................2-6
2.5.1 VHF Radios .......................................................................................................................2-6
2.5.2 UHF Range 1/UHF Range 2 Radios .................................................................................2-6
2.5.3 700–800 MHz Radios........................................................................................................2-7
2.5.3.1 RFPA........................................................................................................................2-7
2.5.3.2 Output Network ........................................................................................................2-7
2.5.3.3 Power Control...........................................................................................................2-7
2.5.3.4 Circuit Protection ......................................................................................................2-7
2.6 Frequency Generation Unit ............................................................................................................2-7
2.6.1 VHF MHz Radios...............................................................................................................2-7
2.6.2 UHF Range 1/UHF Range 2 Radios .................................................................................2-8
2.6.3 700–800 MHz Radios........................................................................................................2-8
2.7 Controller Section...........................................................................................................................2-9
2.7.1 Analog Mode of Operation ................................................................................................2-9
2.7.2 Digital (ASTRO) Mode of Operation................................................................................2-10
2.7.3 Controller Section Circuitry..............................................................................................2-10
Chapter 3 Theory of Operation ............................................................3-1
3.1 Control Head Board........................................................................................................................3-1
3.2 Control Head Board Major Sections...............................................................................................3-1
3.3 Controller Section...........................................................................................................................3-2
3.4 Power Management .......................................................................................................................3-3
3.4.1 Power Distribution .............................................................................................................3-4
3.4.2 Power Up / Power Down Sequence ..................................................................................3-6
3.4.3 Reset Circuits ....................................................................................................................3-6
3.4.4 ATTiny13 Microcontroller Programming............................................................................3-6
3.5 User Interface.................................................................................................................................3-7
3.5.1 LCD Display ......................................................................................................................3-7
3.5.2 Keypad, Volume and Frequency Knob..............................................................................3-7
3.6 GCAI Accessory Interface ..............................................................................................................3-7
3.7 Main Board .....................................................................................................................................3-8
3.8 Main Board Major Sections ............................................................................................................3-8
3.8.1 VHF (136–174 MHz) Band ................................................................................................3-8
3.8.2 UHF Range 1 (380-470 MHz) and UHF Range 2 (450-520 MHz) Band .........................3-11
3.8.3 700–800 MHz Band.........................................................................................................3-13