Magnetic media tester which includes a filter that filters the p

Details Magnetic media tester which includes a filter that filters the p Magnetic media tester which includes a filter that filters the p

1996-12-13

1998-11-17

Snow, Walter E.

Electricity: measuring and testing

Magnetic

Magnetic information storage element testing

360 53, 360 31, 369 53, G01R 3312, G11B 509, G01N 2772

Patent

active

058381538

ABSTRACT:
A disk certifier which analyzes a read signal generated from a disk of a hard disk drive. The read signal typically has a sinusoidal waveform with modulated peak amplitudes. The waveform is generally defined by the equation A.multidot.sin(wt).multidot.(1-m(t)), where the term m(t) is the amplitude modulation of the signal. The peak signal is provided to a phase lock loop circuit which generates a multiplier peak signal generally of the form sin(wt). The certifier includes a multiplier which multiplies the read signal by the multiplier read signal to provide a multiplied read signal described by the equation A/2.multidot.(1-cos 2(wt)).multidot.(1-m(t)). The multiplied read signal is filtered by a low pass filter which has a cut-off frequency Wc below w. The low pass filter provides a filtered multiplied read signal which is described by the equation A.multidot.(1-g(t)), wherein the term g(t) is the portion of m(t) with frequencies below Wc. The filtered multiplied read signal is then compared to a threshold value(s) to determine a pass/fail error condition of the read signal. The certifier also has a histogram circuit which detects, counts and stores the occurrence of each peak amplitude value of the read signal. The peak amplitude data can be processed to plot a histogram which shows how many times the read signal produced various peak amplitudes. The histogram can be used to determine the actual performance of the disk certifier.

REFERENCES:
patent: 5121263 (1992-06-01), Kerwin et al.

Affiliated with

Also associated with

Rating

Magnetic media tester which includes a filter that filters the p does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Magnetic media tester which includes a filter that filters the p, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Magnetic media tester which includes a filter that filters the p will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-887720