Motorola CP180 Informazioni sul servizio - Pagina 9

Sfoglia online o scarica il pdf Informazioni sul servizio per Radio portatile Motorola CP180. Motorola CP180 46. Uhf2 (438-470mhz)
Anche per Motorola CP180: Manuale d'uso di base (16 pagine), Manuale d'uso di base (16 pagine), Manuale d'uso di base (18 pagine), Manuale di servizio dettagliato (28 pagine), Manuale di installazione di Cps/Tuner (6 pagine), Informazioni sul servizio (46 pagine)

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