Magnetic recording/reproducing with added intersymbol interference to obtain a partial-response code

摘要

A magnetic recording/reproducing uses a wide frequency band of a DC component to the next lowest spectral null frequency point and higher by using an existing recording/reproducing head and medium. Intersymbol interference is added to a magnetic recording channel so that an impulse response comes to a partial-response channel shown by polynomial 1-D.sup. n (D.sup.n is an n-bit signal delay); in which T is a Nyquist interval (reproduction-bit time interval), the values of (n 2) and T are selected by assuming equal frequency interval between the spectral null frequency points 1/nT, and thereby a symbol string having a Nyquist frequency equal to or higher than the second spectral null frequency point from the lowest frequency side excluding the vicinity of the DC component of the recording/reproducing characteristic is recorded or reproduced.