Partial-Response Maximum-Likelihood Detection Method for Magneto-Optical Recording

Abstract

We detected bits sized at 0.237 µm bit length and 0.85 µm track pitch recorded by magnetic field modulation on a magneto-optical disk with a 690-nm laser diode and 0.60-numerical-aperture-objective using a partial-response maximum-likelihood detection method. We confirmed that the optimum partial-response for this high linear density had four coefficients of 1 by analyzing difference metrics of error critical paths. The recorded bits with areal density of 5.6 bit/µm2 were also detected at a low error rate, which combination is 0.237-µm bit length and 0.75-µm track pitch. Its write power tolerance is limited to ±22%.

CNR Improvement of Conventional Limdow Media for Higher Density Recording

“…The various techniques to improve of readout method are proposed as it takes much time to shorten wavelength of laser. Partial-Response Maximum-Likelihood (PRML) detection method [1], Magnetically induced Super Resolution (MSR) [2] and Land/Groove recording are major techniques of them. We decides that LIMDOW is the optimum media to add three techniques on because it realize high density recording while read/write speed, reliability and compatibility are being maintained.…”