Motorola CP040 Informacje o usłudze - Strona 9

Przeglądaj online lub pobierz pdf Informacje o usłudze dla Przenośne radio Motorola CP040. Motorola CP040 46 stron. Commercial radios uhf1
Również dla Motorola CP040: Szczegółowa instrukcja serwisowa (28 strony), Informacje o usłudze (48 strony), Podręcznik użytkownika (18 strony), Informacje o usłudze (30 strony)

1.0

This Chapter provides a detailed theory of operation for the UHF1 circuits in the radio. Schematic

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

2.0

UHF (403-440MHz) Receiver

The UHF receiver covers the range of 403-440 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