Patent ID: 7411754
Filing Date: 2008-08-12
Classification: G11B

Abstract:
1. A method for measuring the amplitude asymmetry of a signal from a read head detecting magnetizations in a magnetic recording layer of a magnetic recording disk, the method comprising: writing a first series of magnetizations in the magnetic recording layer to generate readback pulses having a positive amplitude; writing a second series of consecutive magnetizations in the magnetic recording layer to generate readback pulses having a negative amplitude; detecting with the read head the first series of magnetizations to generate a first readback signal; detecting with the read head the second series of magnetizations to generate a second readback signal; measuring in the frequency domain the amplitude of the pulses in said first readback signal; measuring in the frequency domain the amplitude of the pulses in said second readback signal; and calculating from said measured amplitudes the asymmetry between the first readback signal amplitude and the second readback signal amplitude.