摘要:
When an A/D-converted composite video signal is directly outputted while a system clock frequency is switched so as to execute the determination of a signal system, a digital chroma demodulation system prevents the images displayed by the composite video signals from being distorted in accordance with a switching of the frequency of a system clock. The frequency m (=fsc×n) of the system clock is synchronized with a color burst signal and is set to fall in a predetermined range by changing a coefficient n in accordance with the system color burst signal freguency. Thus, since a composite video signal is A/D-converted in accordance with a substantially constant sampling frequency, the sampling condition such as a sampling frequency and a sampling point is not greatly changed.
摘要:
A video signal-processing device that can improve the apparent contrast of the luminance signal at a television receiving set includes a quantity of black expansion computing section for computationally determining the quantity of black expansion when the luminance component of the input video signal is not higher than a first luminance level, a gain controller for regulating the quantity of black expansion as computationally determined by the quantity of black expansion computing section, a quantity of black expansion adding section for generating an output video signal by adding the quantity of black expansion regulated by the gain controller to the luminance component of the input video signal, and a vertical span adding block for integrating the luminance component of the output video signal not higher than a second luminance level for a field. The gain controller regulates the quantity of black expansion according to the luminance component integrated by the vertical span adding block to improve the apparent contrast of the luminance signal at the television receiving set by accurately expanding black.
摘要:
A video signal-processing device that can improve the apparent contrast of the luminance signal at a television receiving set includes a quantity of black expansion computing section for computationally determining the quantity of black expansion when the luminance component of the input video signal is not higher than a first luminance level, a gain controller for regulating the quantity of black expansion as computationally determined by the quantity of black expansion computing section, a quantity of black expansion adding section for generating an output video signal by adding the quantity of black expansion regulated by the gain controller to the luminance component of the input video signals and a vertical span adding block for integrating the luminance component of the output video signal not higher than a second luminance level for a field. The gain controller regulates the quantity of black expansion according to the luminance component integrated by the vertical span adding block to improve the apparent contrast of the luminance signal at the television receiving set by accurately expanding black.
摘要:
In a CRT display and a television set having the same, horizontal/vertical synchronizing signals are separated from a video synchronizing signal in a synchronizing separation circuit, and position information S of a vertical frame is generated on the basis of the horizontal/vertical synchronizing signals in a count-down processor and then converted to corrected vertical frame information W in a function circuit to output a vertical deflection waveform signal and a horizontal deflection correcting waveform signal. Further, the corrected vertical frame information W is compared with predetermined voltages in comparators to detect an effective frame range in the vertical direction.
摘要:
A parabolic wave generator in a color television receiver or the like wherein, when the amplitude level of an input sawtooth wave is higher than the center level thereof, squared currents of mutually reverse polarities obtained by squaring the difference current proportional to the difference voltage between the two levels are added to each other at a predetermined rate, so that one side portion of a nonsymmetrical parabolic wave is produced. Meanwhile, when the amplitude level of the input sawtooth wave is lower than the center level thereof, squared currents of mutually reverse polarities obtained by squaring the difference current proportional to the difference voltage between the two levels are added to each other at another predetermined rate to thereby produce the other portion of the parabolic wave. Consequently it becomes possible to generate the two side portions of mutually different waveforms. And a desired nonsymmetrical parabolic wave can be achieved by combining such two side portions with each other through addition of the currents thereof without raising any problem in regard of the discontinuity or level difference that may otherwise be caused in the vicinity of the peak of the parabolic wave.
摘要:
An active filter apparatus makes it possible for a filter adjusting circuit to require a small number of elements when the filter adjusting circuit is contained in an integrated circuit, to be not easily affected by variations in the characteristics of the elements which form the circuit, and to be capable of easily adjusting the frequency characteristics of the filter to be adjusted. A characteristics conversion device converts, on the basis of an input signal and an output signal of the filter, to a characteristics conversion signal whose amplitude when the adjustment is completed is considerably larger than that of the output signal. As a result, the amplification factor of the characteristics conversion device, necessary to detect a maximum or minimum value of a characteristics conversion signal, is considerably small. Therefore, it is possible to considerably decrease an offset error of the characteristics conversion device.