Digital data reproducing circuit for a magnetic recording apparatus of reproducing digital data without being affected by capable external noise, drop-ins, and drop-outs

摘要

A digital data reproducing circuit suitable for use with a magnetic- recording apparatus comprises first and second comparators, a clock- generating circuit, first and second shift registers, and a discriminator. The first comparator determines when a positive amplitude of a reproduced analog signal exceeds a positive first level. The second comparator determines when a negative amplitude of the reproduced analog signal exceeds a negative first level. The clock generating circuit generates a clock signal phased-locked to timings of positive and negative peaks of the reproduced analog signal. The first shift register receives an output of the first or second comparator in response to the clock signal and shifts and stores such output. The second shift register receives an OR signal of outputs of the first and second comparators in response to the clock signal and shifts and stores such OR signal. The discriminator produces digital data from parallel outputs of the first and second shift registers.