A coding method in digital magnetic recording

An experimental comparison of the recording density limits of three coding methods was performed to find the coding method most suitable for high density recording. We examined FM, MFM, and one of the so-called run-length-limited codes to which self-clocking and peak detection are applicable. In this paper, we call the last coding method "modified nonreturn to zero inverted" (MNRZI). The recording density limit was obtained for each method from measurement of the peak shift and signal to noise ratio for a given recording channel.