Thomson Consumer Electronics Inc.

Roger L Lineberry

William A Lagoni

Gene K Sendelweck

A television receiver includes a 'one-chip' television signal processing IC which has a terminal for receiving a composite video signal including both image and synchronization pulse components. A composite video signal which has been non-linearly processed by a so-called 'black-stretch' circuit is coupled to the composite video signal input terminal of the 'one-chip' IC. In order that a sync separator of the 'one-chip' IC can reliably separate the synchronization pulses from the composite video signal after it has been non-linearly processed, a sync correction circuit, including an auxiliary sync separator, is used to modify the synchronization pulses of the composite video signal after it is non-linearly processed and before it is coupled to the 'one-chip' television IC.

Apparatus for correcting distorted sync in a composite video signal

A composite video input signal is separated into luminance and chrominance components by a signal separation filter and the components are applied to a display processor having a video display device coupled thereto for providing displayed images. For enhancement of detail in dark and light areas of the displayed images, the luminance signal is coupled to the display processor via a non-linear luminance signal processor which provides additional amplification in the dark and light areas but tends also to degrade the signal to noise ratio in those areas. To avoid a loss of signal to noise ratio in the enhanced areas the receiver includes a by-pass circuit for by-passing high frequency components of the luminance signal around the non-linear luminance signal processor and a filter in the non-linear luminance signal processor for attenuating the high frequency components.

Television receiver with partially by-passed non-linear luminance signal

A video switch combines a first video signal with a compressed second video signal for application to a display unit to provide 'picture-in-picture' images in which the first video is displayed in a main picture area of the display and the compressed second video signal is displayed as an inset picture within the main picture area. A non-linear processor, connected between an output of the video switch and an input of the display unit, enhances selected features of the combined video signal displayed by the display unit. Circuit means are provided for controlling the non-linear processor so that non-linear processing is applied to displayed images only in the main picture area and not in the inset picture area.

Television receiver with picture in picture and non-linear processing

Apparatus for separating sync and video includes a luminance signal coupling capacitor, a keyed clamp circuit coupled to a source of back porch keying pulses for clamping a back porch interval of the composite luminance signal to a reference direct voltage level, and signal clipping means comprising at least one voltage follower amplifier device and a threshold biasing semiconductor device of the same conductivity type as the voltage follower amplifier connected to the output electrode of the voltage follower, such that the biasing device maintains the voltage follower in cutoff conduction condition for signals of one polarity with respect to the reference voltage while producing a predetermined direct voltage output across a load resistance and for allowing coupling of signal components of opposite polarity with respect to the direct voltage level to a utilization device.

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Indianapolis, IN, United States of America

Roger L Lineberry