TV signal decoding apparatus using luminance and color signal selection

Abstract

The object of the present invention is to use signal decoding circuits for a first generation EDTV signal and a second generation EDTV signal in common and to suppress an increase of circuit scale. An EDTV signal decoding apparatus of the present invention is constructed with a cascade connection of a first A/D converter, a first signal processing circuit, a first D/A converter, a second A/D converter, a second signal processing circuit and a second D/A converter. The first group composed of the first A/D converter, the first signal processing circuit and the first D/A converter are driven by a clock signal synchronizing with a color burst signal. The second group composed of the second A/D converter, the second signal processing circuit and the second D/A converter are driven by a clock signal synchronizing with a horizontal sync signal. At the first signal processing circuit, a composite video signal is inputted and when a signal discrimination and control circuit judges that a vertical high frequency band helper signal is not multiplexed in upper/lower non-picture periods with the input signal or a vertical high frequency band helper signal is multiplexed in upper/lower non-picture periods but the input signal is in a picture period, a demodulator input signal selector, a luminance signal output selector and I and Q signal output selectors are controlled to be the upper positions and a chrominance signal separated at a three dimensional adaptive type Y/C separator is demodulated at a color demodulator. A luminance signal separated at the three dimensional adaptive type Y/C separator is outputted from a luminance signal output terminal and color signals I and Q demodulated at the color demodulator are outputted from I and Q signal output terminals, respectively.

Dependencies are inferred from the claim text.