HIGH DENSITY BIAS LINEARIZED MAGNETIC RECORDING SYSTEM UTILIZING NYQUIST BAND-WIDTH PARTIAL RESPONSE TRANSMISSION

摘要

HIGH DENSITY BIAS LINEARIZED MAGNETICRECORDING SYSTEM UTILIZING NYQUISTBANDWIDTH PARTIAL RESPONSE TRANSMISSIONABSTRACT OF THE DISCLOSUREA digital magnetic recording system is disclosedthat utilizes partial response signalling to achieve theNyquist data pulse rate with minimum bandwidth. A. C.bias is introduced to linearize the magnetic medium which,inter alia, permits reliable multilevel (greater than 2)data storage without impairing data accessibility. Pre-ferably Class IV partial response is utilized with oneor more sinusoidal lobes in the data frequency spectrum.The basic binary data to be stored is converted to, forexample, ternary and the ternary data is precoded. Theprecoded ternary data is recorded on the magnetic mediumvia an interleaved dipulse sequence having a spectral nullslightly outside the data frequency band. A pilot toneis inserted at the spectral null for timing recovery andautomatic gain control.