LA7555 Просмотр технического описания (PDF) - SANYO -> Panasonic

Номер в каталоге

Компоненты Описание

производитель

LA7555

IF Signal Processing (VIF+SIF) Circuit for TV / VCR Use

SANYO -> Panasonic 

LA7555

Measurement of VIF selectivity characteristics

The pull-in range of the PLL-type VIF IC is approximately ±2MHz. Thus, it is not possible to measure the match-

ing characteristics of the tuner SAW filter easily as with the dummy syncronization detection method. The follow-

ing is just one example of how to measure the selectivity characteristics for a single signal.

Test Circuit

Conditions

1. Apply voltage to the IF AGC (pin 13) and adjust until the video output A is 0.5Vp-p.

2. Atteach a 4.7µF capacitor to the APC filter (pin 20) so that the PLL is unlocked.

3. The waveform shown in the diagram below can be monitored through the externally mounted detector.

Note : Error will occur in the measurement of the selectivity characteristics if the video frequency changes between

A and C (by a video equalizer, etc.)

Externally Mounted Detector (Example)

(1)

(2) Voltage doubler type

No.2927–9/11

Share Link: