LA1867NM Ver la hoja de datos (PDF) - SANYO -> Panasonic

Número de pieza

componentes Descripción

Fabricante

LA1867NM

Car Radio Single-Chip Tuner System

SANYO -> Panasonic 

LA1867NM

Notes on Using the Application Circuits

1. NC Block

• The input impedance of the noise canceller input is about 50 kΩ. Carefully consider the low area frequency

characteristics when determining the value of the coupling capacitor. Note that when the value is 1 µF in the

application circuit, fc will be about 3 Hz.

• Pins 38 and 39 are used to set the noise detection sensitivity and the noise AGC.

The values of the external components can be determined more easily by first setting the medium field (antenna

input levels of about 50 dBµ) with the noise sensitivity setting pin (pin 38), and then setting the weak field (antenna

input levels of about 20 to 30 dBµ) with the AGC adjustment pin (pin 39). Care is required in determining these

settings since while the AGC operation improves as the noise detection sensitivity is increased, inversely, the weak

field sensitivity decreases.

• If noise is detected again during gating, since the monostable multivibrator will be reset, the gate time will change

with the magnitude of the noise. Finally, set the gate time from the point noise is detected. When the circuit

constants in the circuit connected to pin 40 are C = 0.001 µF and R = 12 kΩ, the gate time will be about 10 µs.

2. MRC Block

• The MRC (multipath rejection circuit) supports three techniques as shown in Figures 2, 3 and 4. Figure 2 shows the

technique in which the S-meter AC component is detected directly. Figure 3 shows the technique in which the NC

HPF noise is detected, and Figure 4 shows the technique in which multipath is detected using the S-meter high area

components.

Figure 2 Multipath Circuit

Figure 3 Application Circuit Using NC HPF Noise Detection

No. 4619-21/32

Share Link: