Circuit Description; General Overview; Introduction; Pc Boards - E.F. Johnson Company 5100 ES Series Service Manual

S
E C T I O N

Circuit Description

Chapter 5
5.1

General Overview

5.1.1

Introduction

®
The EFJohnson 5100 ES Portable Radio uses a PowerPC -based controller and a Digital
Signal Processor (DSP) to provide the following modes of operation:
Narrowband Analog - FM modulation with a maximum deviation of 2.5 kHz. This mode
is usually used in systems where the channel spacing is 12.5 kHz. Call Guard (CTCSS or
DCS) subaudible squelch signaling can be used in this mode.
Wideband Analog - FM modulation with a maximum deviation of 5 kHz. This mode is
usually used in systems where the channel spacing is 25 kHz or 30 kHz. Call Guard
(CTCSS or DCS) subaudible squelch signaling can be used in this mode.
Project 25 Digital - The voice is digitized, error corrected, optionally encrypted and
transmitted using C4FM modulation according to the Project 25 standard. This mode can
be used in channel spacings of 12.5 kHz.
The DSP processes the received signals and generates the appropriate output signals. The
microcontroller controls the hardware and provides an interface between hardware and
DSP.
5.1.1.1

PC Boards

This radio contains the following PC boards:
• RF Board
• Logic Board
January 2007 5100 ES Series Portable Radio Service Manual 5-1