Basic Theory Of Operation; General Overview; Figure 1. Xts 2500 Overall Block Diagram - Motorola XTS 2500 Basic Service Manual

Basic Theory of Operation

General
Overview
The ASTRO Digital XTS 2500 radio is a wideband, synthesized, fixed-tuned radio
available in the 700/800 MHz bands. All XTS 2500 radios are capable of both analog
operation (12.5 kHz or 25 kHz bandwidths) and digital ASTRO mode operation (12.5 kHz
only).
The ASTRO Digital XTS 2500 radio includes the following major assemblies (see Figure
1):
• Main Board: contains the microcontrol unit (MCU) and its associated memory and
memory management integrated circuit (IC), the audio power amplifier, and a
switching regulator. The board also contains the digital signal processor (DSP) and its
support IC and associated memories. It further contains all transmit, receive, and
frequency generation circuitry, including the digital receiver back-end IC and the
reference oscillator.
• Universal Flex: contains the universal connector, speaker, and microphone.
• Display (Models II and III only): a six-line, 12-character, liquid-crystal display
(LCD).
• Keypad (Models II and III only):
- Model II: a 3 x 2 keypad
- Model III: a 3 x 6 keypad.
Universal
Flex
13
(Side Connector,
Controls, LEDs,
Speaker,
Microphone)
Keypad
20
Note:
indicates 20
wires
Display

Figure 1. XTS 2500 Overall Block Diagram

20
J650
Main
Board
45
J601
22
3
Antenna
J101
3
7.5V
B500
Battery
5