Digital demodulator with a unit for correcting over modulation and preventing black reversing

A digital demodulator comprising:

• a reproducing head for reproducing an analog video signal from a recording medium;
• an analog to digital converter for converting the analog video signal from said reproducing head into a digital signal;
• a Hilbert transform circuit for transforming the digital signal into transformed signals whose phases are shifted by first and second angles from a phase of the digital signal, respectively;
• a frequency detector for detecting a frequency of the transformed signals;
• first coefficient calculation means for producing a weighting coefficient from an output signal of said frequency detector;
• second coefficient calculation means for producing a weighting coefficient from the transformed signals;
• a multiplier for multiplying together the weighting coefficients from said first and second coefficient calculation means and producing a correction signal;
• an equalizer receiving said correction signal and said transformed signals for correcting a frequency characteristic of the transformed signals in response to said correction signal;
• and
• a demodulator for demodulating an output signal of said equalizer, wherein the frequency characteristic of said equalizer is corrected in accordance with said correction signal from said multiplier.