Motorola SSETM 5000 service manual Theory of Operation, Major Assemblies

Chapter 2 Theory of Operation

This chapter provides a detailed circuit description of the SSE 5000 transceiver and VOCON boards. 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 SSE 5000 radio is a dual-mode (digital/analog), 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 SSE 5000 radio operates within the UHF range (450 to 488 MHz).

2.1Major Assemblies

The SSE 5000 radio includes the following major assemblies (see Figure 2-1):

•VOCON 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.

•Transceiver (XCVR) Board — contains all transmit, receive, and frequency generation circuitry, including the digital receiver back-end IC and the reference oscillator.

•Controls/Universal Flex — contains on/off/volume switch, channel select switch, push-to-talk (PTT) switch, monitor button, several function-selectable switches, universal connector, speaker, and microphone.

•Display — 112 pixels x 32 pixels bit-mapped, liquid-crystal display (LCD).

12

Note: Indicates 12 wires

External 12

Accessory

Connector

7.5V	3
Battery

Internal Speaker

& Mic Flex

Control

Top

Display

Universal

Flex

4

20

20

14

M102

P201

J707

VOCON

Board

J301

J102

J701

26

40

		Standard
		Antenna
P1	J101
Transceiver		Remote
	Board	Antenna
	J102
	J1	3
Encryption
	Module
	(Optional)

MAEPF-27277-B

Figure 2-1. SSE 5000 Overall Block Diagram