Abstract: A color television receiver having an automatic white control circuit which includes a detection circuit for detecting whether or not a given magnitude of a cathode current of a CRT flows, and generating a detection signal when the cathode current exceeds the given magnitude; and an interruption circuit for interrupting the supply of a video signal to the CRT until a given period of time has elapsed after the generation of the detection signal. The heat-up of the cathode of CRT is detected by the generation of the detection signal. The interruption circuit makes the CRT free from the video signal for the given period of time after the heat-up, so that no raster with maximum brightness appears after the power-on of the television receiver.

Abstract: In this invention, by using first and second 1H delay means, first to third band pass means near 3.58 MH.sub.H, first to third polarity inverting means, first to fifth adding means and first to third intermediate value detecting circuits, from a composite video signal fed as an input, a chrominance signal in which no luminance signal component is mixed can be obtained, a chrominance signal having no such resolution reduction as dulling in the vertical direction can be obtained and a luminance signal having no chrominance signal component mixed in and having no such resolution reduction as dulling in the vertical direction can be obtained. Further, a chrominance signal component can be effectively separated in the edge part of a video image in which the luminance variation is large.

Abstract: A contour correction circuit applies a preshoot and overshoot to the rising and falling edges of an original signal waveform and supplies a contour-corrected signal with an emphasized contour, as a first signal, to maximum level circuits. The original signal which is time-advanced ahead of the first signal is supplied as a second signal to the maximum level circuit. The original signal, time-delayed by a delay element behind the first signal, is supplied as a third signal to the maximum level signal. The first and third signals are supplied to a maximum level circuit. The output of the maximum level circuits is supplied to a minimum level circuit. The minimum level circuit produces an output signal with the preshoot and overshoot of the first signal eliminated and with the rising and falling edges sharply defined with respect to the original signal.

Abstract: A liquid crystal display device includes a liquid crystal display, which has a plurality of liquid crystal elements arranged in a matrix and has signal electrodes and scanning electrodes provided with respect to the liquid crystal elements. A signal electrode driver, for driving the signal electrodes of the liquid crystal display, has a driver and a switch circuit. This switch circuit comprises groups of switches connected in multi-stages in the column direction. Each switching stage includes a plurality of switches, the number of which increases from one stage to another toward the final stage. The switches of the first switching stage have their input terminals supplied with video signals, respectively. The output terminal of each switch of one switching stage is branched and coupled to the input terminals of associated switches of the succeeding stage. The output terminals of the switches of the last switching stage are respectively coupled to the signal electrodes.

Abstract: A color television receiver with automatic reference white control circuit has negative feedback loops for automatically adjusting the amplitude of each cathode driving voltage of R, G and B electron guns, so that the magnitude of each cathode current of R, G and B electron guns is converged to a given value. According to the negative feedback operation, an adjusted reference white becomes insensitive to changes in the cathode emission of CRT due to aging.

Abstract: A vertical contour correction device for imparting preshoot and overshoot to a video signal from a video source and correcting the vertical contour of the video signal in the vertical direction as well as the horizontal direction. The contour device utilizes only a single delay means and a plurality of amplifiers which have their gains and polarities fixed at a predetermined relationship with one another.

Abstract: The vertical contour correction device in accordance with the present invention comprises a first addition circuit for receiving a video signal from the video signal source as a first signal, for the purpose of combining a first signal and a second signal, a delay line connected with its input terminal to the output terminal of the first addition circuit, for taking out, at its output terminal, a signal supplied to its input terminal by delaying it by the duration of one horizontal scan, a subtraction circuit for mixing subtractively the signal obtained at the output terminal of the delay line and the first signal, a feedback network for supplying to the first addition circuit with the output signal of the subtraction circuit, as a second signal, by processing it to have a lower level and opposite polarity relative to the first signal, and a second addition circuit for taking out a video signal with preshoot and overshoot by mixing additively and at a prescribed ratio the signal obtained at the output termina