Sperry Rand Corporation

Arthur P Geffon

George V Jacoby

Robert Price

Magnetic recording apparatus including signal equalization means for recording data so as to obtain read pulses therefrom which are symmetrical about their peak and substantially narrowed at both the base and half amplitude points whereby increased packing density may be achieved without attendant peak shift, the equalization being provided by means for generating an ac bias signal in conjunction with data transitions and associated equalizer transitions referenced to the bias signal for application to magnetic recording means.

Magnetic recording signal equalization apparatus

A circuit for accurately detecting the zero crossing points of a data signal. Noise in the signal is eliminated by deleting all noise present on the signal having an amplitude or a width less than a predetermined value prior to detecting the crossover points.

Circuit for detecting zero crossing points for data signal

A dual channel signal detector circuit comprising an equalizer for responding to a variable peak amplitude input signal, in which the peaks are representative of data, so as to provide a substantially constant peak amplitude output signal having discrete data representative pulses spaced along a base line, which is substantially flat at the zero level in regions intermediate the pulses, for application to separate peak detection and amplitude detection channels. The peak detection channel produces data pulses each indicative of the relative time occurrence of the peak of a respective data representative pulse while the amplitude detection channel is triggered by signal levels of the data representative pulses exceeding a predetermined threshold to produce gating pulses for gating the data pulses to the circuit output substantially exclusive of any noise that may be present at the input of the circuit.

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Sunnyvale, CA, United States of America

Arthur P Geffon