US 7,583,322 B2 · Television and adjustment method for the same

Abstract

A pedestal level of each of the R-Y and B-Y signals (color-difference signals) in a horizontal synchronization time T1 of a horizontal synchronizing signal is detected, and a pedestal level adjustment value for adjustment of the pedestal level of each of the R-Y and B-Y signals is determined based on the pedestal level determined in such a manner that a difference in pedestal level of each of the R-Y and B-Y signals between in the horizontal synchronization time T1 and in a horizontal scanning time T2 of the horizontal synchronizing signal is lessen. The pedestal level adjustment value determined is stored and video amplification-chroma circuit 130 adjusts the pedestal level of each of the R-Y signal and the B-Y signal in the horizontal synchronization time T1 of the horizontal synchronizing signal by an amount of adjustment value stored in.

A television comprising:

a video amplification-chroma circuit for generating a sawtooth-like drive signal and three primary color signals from a component video signal inputted thereto, the component video signal including a luminance signal with vertical and horizontal synchronizing signals superimposed thereon, a red color-difference signal (V), and a blue color-difference signal (U);
a microcomputer for controlling processing to be performed by the video amplification-chroma circuit;
a video output circuit for amplifying the three primary color signals;
a picture tube for emitting an electron beam therein using high voltage inputted thereto, and for receiving the amplified primary color signals inputted thereto and displaying an image corresponding to the component video signal;
a deflection circuit for generating a high-frequency signal and a drive current from the drive signal inputted thereto;
a high voltage circuit having a flyback transformer for supplying the picture tube with the high voltage generated from the high-frequency signal inputted thereto;
a deflection coil for receiving input of the drive current and driving the electron beam emitted within the picture tube;
an amplification circuit for amplifying the respective red and blue color-difference signals with reference to a ground potential to generate respective amplified signals for V and U;
and
a smoothing circuit for smoothing the respective amplified signals for V and U generated,
the video amplification-chroma circuit comprising:
a separating circuit for separating the vertical and horizontal synchronizing signals from the component video signal;
a semiconductor memory for storing therein a pedestal level adjustment value for V for adjustment of a pedestal level of the red color-difference signal, the pedestal level adjustment value for V having any one of a plurality of stepwise values, and a pedestal level adjustment value for U for adjustment of a pedestal level of the blue color-difference signal, the pedestal level adjustment value for U having any one of a plurality of stepwise values;
and
a pedestal level adjustment circuit for adjusting the pedestal level of the red color-difference signal by an amount of adjustment according to the pedestal level adjustment value for V stored in the semiconductor memory, and for adjusting the pedestal level of the blue color-difference signal by an amount of adjustment according to the pedestal level adjustment value for U stored in the semiconductor memory in a horizontal synchronization time of the horizontal synchronizing signal separated by the separating circuit,
the television being operable to display the image from the picture tube based on the component video signal obtained after the adjustment,
wherein the microcomputer includes an analog/digital conversion circuit for generating an amplified signal value for V and an amplified signal value for U in digital form corresponding to and from the amplified signals for V and U smoothed by the smoothing circuit, respectively,
wherein the microcomputer is adapted to generate the amplified signal values for V and U in a state where the red and blue color-difference signals are not being inputted into the video amplification-chroma circuit, to select and determine the pedestal level adjustment value for V from the plurality of stepwise values, based on said amplified signal value for V generated in the state, in such a manner that the amplified signal value for V generated by the analog/digital conversion circuit takes a value that is most close to zero, as well as the pedestal level adjustment value for U from the plurality of stepwise values, based on said amplified signal value for U generated in the state, in such a manner that the U amplified signal value generated by the analog/digital conversion circuit takes a value that is most close to zero, and to output the pedestal level adjustment value for V and the pedestal level adjustment value for U determined to the video amplification-chroma circuit,
wherein the video amplification-chroma circuit is adapted to store in the semiconductor memory the pedestal level adjustment value for V and the pedestal level adjustment value for U inputted from the microcomputer, thereby decreasing deviation in the pedestal level of each of the red and blue color-difference signals in the horizontal synchronization time which deviation may be caused by electric noise jumped into the red and blue color-difference signals from the flyback transformer during the horizontal synchronization time.

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Television and adjustment method for the same

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Television and adjustment method for the same

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Abstract

Claims6