Digital non-linear pre-emphasis/de-emphasis apparatus for video signals in a video signal recording and reproducing apparatus

A digital non-linear pre-emphasis apparatus comprising:

• a first high-pass filter comprising a finite impulse response filter for detecting high band components of an input digital signal;
• a non-linear coefficient processor for multiplying said input digital signal by a first non-linear coefficient responsive to amplitude of detected said high-band components so as to change gain of said input digital signal to thereby output a gain-varied signal;
• a second high-pass filter receiving said gain-varied signal comprising an infinite impulse response filter for multiplying said gain-varied signal by a second non-linear coefficient responsive to an amplitude thereof to thereby change a passband thereof so as to output a passband-varied signal;
• and
• an arithmetic operator for adding said input digital signal to said passband-varied signal to thereby generate a pre-emphasized signal according to a predetermined operation.

A digital non-linear de-emphasis apparatus for de-emphasizing a pre-emphasized digital input signal, comprising:

• a subtractor for subtracting a de-emphasis amount from the pre-emphasized digital input signal, for restoring the pre-emphasized digital input signal to an original signal having a non-emphasized digital signal form and providing said original signal;
• a first high-pass filter comprising a finite impulse response filter for detecting an amplitude of high-band components of the original signal output from said subtractor;
• a non-linear coefficient processor for multiplying a pre-emphasized digital input signal based on said original signal by a first non-linear coefficient responsive to the detected amplitude of said high-band components of said original signal to thereby change the gain of said pre-emphasized digital input signal to thereby output a gain-varied pre-emphasized digital signal as a gain-varied signal;
• and
• a second high-pass filter comprising an infinite impulse response filter for multiplying the gain-varied signal of said non-linear coefficient processor by a second non-linear coefficient responsive to the amplitude thereof for changing a passband thereof so as to output a passband-varied output signal corresponding to said de-emphasis amount to said subtractor.

A digital non-linear pre-emphasis/de-emphasis apparatus, comprising:

• a first switch having a first contact point which serves as an input port during a recording mode and a second contact point which serves as an output port during a reproduction mode, said first switch selecting one of said first and second contact points to be connected according to a predetermined record/reproduction mode signal;
• a second switch having a third contact point which serves as an output port during a recording mode and a fourth contact point which serves as an input port during a reproduction mode, said second switch selecting one of said third and fourth contact points to be connected according to said predetermined record/reproduction mode signal;
• a selectable operator connected between said first and said second switches for adding during said recording mode and for subtracting during said reproduction mode an emphasis amount to, during said recording mode, and from, during said reproduction mode, the input signal which is input through one of said first and said second switches, according to said record/reproduction mode signal;
• a first filter for varying gain of said input signal according to an amplitude of the signal which is input via one of said first and said second switches to output a said gain-varied signal;
• and
• a second filter for varying a passband of the output of said first filter according to an amplitude thereof, to thereby output a passband-varied signal corresponding to an emphasis amount to said selective operator.

A digital non-linear pre-emphasis/de-emphasis apparatus, comprising:

• a first switch having a first contact point which serves as an input port during a record mode and a second contact point which serves as an output port during a reproduction mode, said first switch selecting a corresponding contact point to be connected according to whether a predetermined record/reproduction mode signal indicates said record mode or said reproduction mode;
• a second switch having a third contact point which serves as an output port during said record mode and a fourth contact point which serves as an input port during said reproduction mode, said second switch selecting a corresponding contact point to be connected according to whether said predetermined record/reproduction mode signal indicates said record mode or said reproduction mode;
• a selectable operator connected between said first and said second switches for respectively, adding during said recording mode and for subtracting during said reproduction mode an emphasis amount to, during said recording mode, and from, during said reproduction mode, an input signal which is input through one of said first and said second switches, according to said record/reproduction mode signal;
• a first high-pass filter comprising a finite impulse response filter for detecting high-band components of a digital signal which is input via said first switch or said second switch;
• a first non-linear coefficient processor for multiplying said input digital signal by a first non-linear coefficient responsive to an amplitude of the detected said high-band components thereof to thereby change the gain thereof so as to output a gain-varied signal;
• and
• a second high-pass filter comprising an infinite impulse response filter for multiplying an output of said first non-linear coefficient processor by a second non-linear coefficient responsive to respective amplitudes to thereby vary a passband so as to generate a passband-varied signal corresponding to an emphasis amount provided to said operator.