Video signal processing circuit of a video signal recorder/reproducer

A video signal reproducing circuit, comprising:

• standard luma reproducing means for reproducing a composite video signal recorded on a record medium via a reproducing head, and for reproducing a luma signal having a high frequency component folded into a low frequency component included in said composite video signal;
• standard chroma/motion signal reproducing means for reproducing a chroma/motion signal representing a chroma and motion signal from said composite video signal;
• luma signal preprocessor means connected to said standard luma reproducing means, for clamping and analog-to-digital converting said luma signal, and for generating a first time base-corrected signal;
• chroma/motion signal preprocessor means connected to said standard chroma/motion signal reproducer, for clamping and analog-to-digital converting said chroma/motion signal, and for generating a second time base-corrected signal;
• chroma/motion signal separator means for separating said second time base-corrected signal into chroma and motion signals;
• adaptive unfolding means for receiving said first time base-corrected signal from said luma signal preprocessor means, for removing a folding signal included in said first time base corrected signal in accordance with an amplitude of said motion signal separated from said second time base-corrected signal, and for adaptively unfolding the high frequency component folded into the low frequency component of said first time-base corrected signal to output the unfolded luma signal;
• and
• composite video signal generating means for digital-to-analog converting the signals which are supplied from the adaptive unfolding means, and said chroma/motion signal separator means, respectively, and mixing the analog-converted signals to output a composite video signal;
• said adaptive unfolding means comprising:
• unfolding means for removing the folding signal from the signal supplied from the luma signal preprocessor means, and for unfolding and outputting said high frequency component folded into the low frequency component of said first time base corrected signal;
• first low-pass filter means for low-pass filtering the unfolded luma signal supplied from said unfolding means;
• first high-pass filter means for high-pass filtering signals supplied from said unfolding means and from the first output terminal of said first low-pass filter means;
• band-pass filter means for band-pass filtering a signal supplied from the first output terminal of said first low-pass filter means;
• second low-pass filter means for low-pass filtering a signal supplied from said bandpass filter means;
• second high-pass filter means for high-pass filtering signals supplied from said bandpass filter means and from said second low-pass filter means;
• inverting means for inverting a signal supplied from said second low-pass filter means;
• level compensating means for compensating frequency levels of signals supplied from said inverting means and from said second high-pass filter means;
• level detecting means for detecting an amplitude of a signal supplied from said first high-pass filter means, and for supplying to said first low-pass filter means and said level compensating means a detected level signal indicative of said amplitude;
• and
• mixing means for receiving the signals supplied from the second output terminal of said first low-pass filter means and from said level compensating means, and for outputting a signal exhibiting a restored high frequency amplitude.

In a video recording device including a folding circuit for folding a high frequency component of level adjusted video signals into a low frequency component of said level adjusted video signals and a level adjusting portion for lowering an amplitude of a high frequency component of received video signals relative to a low frequency component of said received video signals to generate said level adjusted video signals, said level adjusting portion comprising:

• level detecting means for generating control signals indicative of detected levels of said received video signals;
• first low pass filtering means for low pass filtering said received video signals;
• band pass filtering means for band pass filtering in response to said received video signals;
• first means for high pass filtering being responsive to an output of said band pass filtering means;
• second means for low pass filtering being responsive to an output of said band pass filtering means;
• level compensating means, responsive to said second low pass filtering means and said first high pass filtering means, for level compensating in dependence upon said control signals;
• and
• mixing means, responsive to outputs of said first low pass filtering means and said level compensating means, for generating said level adjusted video signals.

A video signal recording device, comprising:

• means for separating chrominance signals from a composite video signal;
• means for separating luminance signals from said composite video signal;
• level detecting means for generating control signals indicative of detected levels of said luminance signals;
• first low pass filtering means for low pass filtering said luminance signals;
• band pass filtering means for band pass filtering in response to said luminance signals;
• first means for high pass filtering being responsive to an output of said band pass filtering means;
• second means for low pass filtering being responsive to an output of said band pass filtering means;
• level compensating means, responsive to outputs of said second low pass filtering means and said first high pass filtering means, for level compensating in dependence upon said control signals to lower an amplitude of a high frequency component of said luminance signals relative to a low frequency component of said luminance signals;
• means for mixing being responsive to outputs of said low pass filtering means and said level compensating means;
• and
• means for holding said high frequency component of said luminance signals into said low frequency component of said luminance signals received from said mixing means.

A luminance signal processing circuit, comprising:

• level detecting means for generating control signals indicative of detected levels of input luminance signals;
• first low pass filtering means for low pass filtering said input luminance signals;
• band pass filtering means for band pass filtering in response to said input luminance signals;
• first means for high pass filtering being responsive to n output of said band pass filtering means;
• second means or low pass filtering being responsive to an output of said band pass filtering means;
• level compensating means, responsive to outputs of said second low pass filtering means and said first high pass filtering means, for level compensating in dependence upon said control signals;
• and
• means for mixing being responsive to outputs of said first low pass filtering means and said level compensating means.

In a video reproducing device including a decoding circuit for unfolding received video signals, a level adjusting portion for increasing a level of a high frequency component of the unfolded video signals relative to a low frequency component of said unfolded video signals, said level adjusting portion comprising:

• level detecting means for generating control signals indicative of detected levels of said unfolded video signals;
• first low pass filtering means for low pass filtering said unfolded video signals;
• band pass filtering means for band pass filtering said unfolded video signals;
• first high pass filtering means for generating a high pass filtered signal by high pass filtering a signal output of said band pass filtering means;
• second low pass filtering means for generating a low pass filtered signal by low pass filtering a signal output of said band pass filtering means;
• level compensating means, responsive to said low pass filtered signal and said high pass filtered signal, for level compensating in dependence upon said control signals;
• and
• mixing means, responsive to said first low pass filtering means and said level compensating means, for generating level adjusted video signals.

A video signal encoding device, comprising:

• first low pass filtering means for generating first low pass filtered video signals by low pass filtering received video signals;
• band pass filtering means for generating band pass filtered video signals in response to said received video signals;
• first high pass filtering means for generating first high pass filtered video signals;
• by high pass filtering said band pass filtered video signals;
• second low pass filtering means for generating second low pass filtered video signals by low pass filtering said band pass filtered video signals;
• level compensating means for generating level compensating signals in response said first high pass filtered video signals, said second low pass filtered video signals, and control signals, said control signals being indicative of detected levels of said received video signals;
• mixing means for generating level compensated video signals by mixing said first low pass filtered signals and said level compensating signals;
• and
• means for folding a high frequency component of said level compensated video signals onto a low frequency component of said level compensated video signals.

A video signal decoding device, comprising:

• unfolding means for generating unfolded video signals by unfolding a high frequency component of received video signals from a low frequency component of said received video signals;
• first low pass filtering means for generating first low pass filtered video signals by low pass filtering said unfolded video signals;
• band pass filtering means for generating band pass filtered video signals in response to said unfolded video signals;
• first high pass filtering means for generating first high pass filtered video signals by high pass filtering said band pass filtered video signals;
• second low pass filtering means for generating second low pass filtered video signals by low pass filtering said band pass filtered video signals;
• level compensating means for generating level compensating signals in response said first high pass filtered video signals, said second low pass filtered video signals, and control signals, said control signals being indicative of detected levels of said unfolded video signals;
• and
• mixing means for generating level compensated video signals by mixing said first low pass filtered signals and said level compensating signals.