| 摘要 |
PROBLEM TO BE SOLVED: To improve recording density regardless of a recording medium and a modulation system. SOLUTION: Digital information signals are modulated by using a so-called (d, k) RLL code in an RLL coder 2, where d is the minimum run length and k is the maximum run length, and recorded in a recording medium 3. The signals reproduced from the medium 3 are equalized in an equalizer 4 and deciphered into the original digital information signals in a decoder 5. A frequency characteristic E(f) of the equalizer 4 is set so that an overall transmission frequency characteristic H(f) to an impulse becomes the cosine characteristic shown by expression I H(f)=cos((π/2)×(f/Fm)). In the expression I, Fm is the high frequency cutoff frequency of the medium 3 or the frequency shown by expression II Fm=Fb'/(d×K). In the expression II, K is a recording density improvement coefficient. |
