Chapter 3 Basic Theory Of Operation; Major Assemblies; Figure 3-1. Xts 4000 Overall Block Diagram - Motorola Astro XTS 4000 Service Manual

Chapter 3 Basic Theory of Operation

This chapter discusses the basic operational theory of the ASTRO XTS 4000 radio, which is a
wideband, synthesized radio available in the VHF (136–174 MHz) and UHF (380–470 MHz)
frequency bands. All ASTRO XTS 4000 radios are capable of ASTRO mode (digital) operation
(12.5 kHz).
3.1

Major Assemblies

The ASTRO XTS 4000 radio includes the following major connections to the main board
(See Figure 3–1):
• Main Board – contains a dual-core processor which includes both the microcontroller unit
(MCU) and a digital signal processor (DSP) core, the processor's memory devices, an audio
and power supply support integrated circuit (IC), a digital support IC, and the audio power
amplifier. It also contains all transmit, receive, and frequency generation circuitry, including the
digital receiver back-end IC and the reference oscillator.
• CE-UCM Flex – contains vibrator, speaker, microphone and encryption connector.
• Main Display – 130 x 130 dot matrix, liquid-crystal display (LCD).
• CID Display – 112 x 32 dot matrix, liquid-crystal display (LCD).
• Keypad – a 3 x 3 Menu keypad with 4-way navigation button, and a 3 x 4 alphanumeric
keypad.
Display, Keypad and
External
Accessory
Connector
Vibrator
Speaker and
Microphone
Earpiece
Controls
CE
Connector
2
Encryption
Module
3
Audio jack
Figure 3–1. XTS 4000 Overall Block Diagram
60
16
J3
8
Main Board
7 30
J2
3
Antenna
J1
3
7.5V
Battery