Circuit Description

The following functional units are integrated in this circuit combination for processing multi standard television IF signals:

The IF signal is supplied to the synchronous demodulator via a three-stage gain controlled wideband amplifier. A level detector limits the output voltage of the wideband amplifier in the event of overdrive.

The required switching carrier for the demodulator is obtained from the IF signal of the wideband amplifier by means of a selection and limiter stage. A delay network is connected upstream of the demodulator in order to compensate phase differences.

The polarity of the switching carrier at the output of the limiter stage can be reversed with the standard switch (Pin 12), with the result that negatively or positively modulated IF signals appear at the demodulator output with the same polarity. The demodulated video signal is filtered and amplified and is supplied to the video output (Pin 9) via a noise limiter stage.

Features

● Standard B/G-L suitable, processes negatively and positively modulated IF-signals with equal polarity of the output signal

● Ultra white inverter and ultrablack limiter for reducing transmission interference

● Internally noise protected gain control, no flyback pulses required

● Expanded video frequency response allows the demodulation of amplitude modulated MAC signals

● High input sensitivity

● Minimal intermodulation distortions

● Small differential error

● Fast AGC by controlled discharge of the AGC capacitor

● Standard L mode: AGC acting on peak white level, capacitor discharge control by averaged video signal Standard B/G: AGC acting on the sync. pulse peak

● Constant input impedance

● Video output voltage with narrow tolerance

● Video input/output for insertion of external sound trap

● VTR input/output with video switch

● Adjustable, delayed AGC for the tuner

● ESD protected

Case: DIP18