Motorola Commercial Series Информация о сервисе - Страница 9

Просмотреть онлайн или скачать pdf Информация о сервисе для Портативное радио Motorola Commercial Series. Motorola Commercial Series 46 страниц. Uhf2 (438-470mhz)
Также для Motorola Commercial Series: Базовое руководство пользователя (16 страниц), Информация о сервисе (48 страниц), Руководство пользователя (18 страниц), Базовое руководство пользователя (12 страниц), Информация о сервисе (30 страниц)

1.0

This Chapter provides a detailed theory of operation for the UHF circuits in the radio. Schematic

diagrams and board layout diagrams are included in Chapter 4 in this Section of the manual.

2.0

UHF (438-470MHz) Receiver

The UHF receiver covers the range of 438-470 MHz and provides switchable IF bandwidth for use

with 20/25/30 kHz or 12.5 kHz channel spacing systems. The receiver is divided into two major

blocks, as shown in Figure 2-1.

Front End

Back End

RX from

Antenna Switch

Preselector

Filter

Amp

First LO

from Synthesizer

Recovered Audio

RSSI

Figure 2-1 UHF Receiver Block Diagram

THEORY OF OPERATION

Interstage

Crystal

Filter

1st Mixer

Inj Filter

Ceramic

Resonator

Demodulator

12.5kHzFilter

Chapter 2

Amp

Filter

BW_SEL

Cer Fltr

Switching