6871620L01-C
May 28, 2008
Theory of Operation:
General
3-1
Chapter 3 Theory of Operation
This chapter provides a detailed circuit description of the ASTRO XTS 4000 mainboard (contains RF
transceiver and VOCON sections). When reading the theory of operation, refer to the appropriate
schematic and component location diagrams located in the back of this manual. This detailed theory
of operation can help isolate the problem to a particular component.
The ASTRO XTS 4000 digital portable radio is a microcontroller-based transceiver incorporating a
digital signal processor (DSP). The microcontroller handles the general radio control, monitors
status, and processes commands input from the keypad or other user controls. The DSP processes
the typical analog signals, and generates the standard signaling digitally to provide compatibility with
existing analog systems. In addition, the DSP provides digital modulation techniques, utilizing voice
encoding techniques with error correction schemes. This provides the user with enhanced range and
audio quality, all in a reduced bandwidth channel requirement. It allows embedded signaling, which
can mix system information and data with digital voice to support a multitude of system features.
The ASTRO XTS 4000 radio (
) consists of the following:
• Band-dependent mainboard (contains RF Transceiver and VOCON sections)
• Front Flip Assembly (containing Display, Keypad and Encryption Module)
• Radio Chassis Assembly (containing Audio Jack, CE Interface Connector
and Controls)
Figure 3-1. XTS 4000 Overall Block Diagram
Front Flip
Assembly
Main & CID
Display
Keypad
Encryption Module
Earpiece
Speaker,
Microphone, Haptic
Device
Radio
Chassis
Assembly
CE Interface
Audio Jack
Controls
J1
60
J2
J3
16
30
Battery
M1705
3
M1704
Antenna
1
VOCON
Section
RF
TRANSCEIVER
Section
MAINBOARD
Front Flip
Assembly
Main & CID
Display
Keypad
Encryption Module
Earpiece
Speaker,
Microphone, Haptic
Device
Radio
Chassis
Assembly
CE Interface
Connector
Audio Jack
Controls
J1
60
J2
J3
16
30
Battery
M1705
3
M1704
Antenna
1
VOCON
Section
RF
TRANSCEIVER
Section
MAINBOARD
Summary of Contents for ASTRO XTSTM 4000
Page 1: ...COLOR CHORDS 7 ASTRO XTSTM 4000 Portable Radio Detailed Service Manual ...
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Page 16: ...May 28 2008 6871620L01 C xiv Commercial Warranty Notes ...
Page 22: ...May 28 2008 6871620L01 C 1 6 Introduction Notes ...
Page 26: ...May 28 2008 6871620L01 C 2 4 Radio Power Notes ...
Page 56: ...May 28 2008 6871620L01 C 3 30 Theory of Operation Notes ...
Page 100: ...May 28 2008 6871620L01 C 6 8 Troubleshooting Waveforms Notes ...
Page 194: ...May 28 2008 6871620L01 C B 2 Motorola Service Centers Notes ...
Page 204: ...May 28 2008 6871620L01 C Glossary 10 Glossary Notes ...
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