A study on detection methods of NRZ recording

In high-density magnetic recording, since the level of playback signal is low, its instrument noise margin may become seriously reduced, especially in view of the level fluctuation of the playback signal caused by tape-to-head spacing variations. Moreover, in high track density recording, the leakage from neighboring recorded tracks can importantly influence conclusions about overall system performance. Three detecting methods within the class of NRZ pulse recording formats have been compared: integrated detection of NRZ recording, amplitude detection of precoded NRZI recording, and partial response detection of precoded Interleaved NRZI recording. The comparisions are made with respect to the signal-to-noise ratio due to instrument noise in the playback process, the variation of separation allowed between the tape and head in the playback process, and the interference caused by leakage from adjacent recorded tracks. The results show the partial response detection method to promise the largest areal density among these three detection methods.