Patent ID: 9305584
Filing Date: 2016-04-05
CPC Classification: G11B

Claim Text:
1. A magnetic disk device comprising: a magnetic head including a write head with a high-frequency oscillator and a read head; a recording medium to and from which data is written and read by the magnetic head; a driving unit configured to move the magnetic head on the recording medium; a measuring unit configured to obtain a first read signal and a second read signal, the first read signal being obtained by reading a first data pattern written when no current is supplied to the high-frequency oscillator or a smaller current than in a writing operation to the recording medium is supplied to the high-frequency oscillator, the second read signal being obtained by reading a second data pattern written when a current supplied in the normal writing operation to the recording medium is supplied to the high-frequency oscillator; a comparison unit configured to calculate comparative data indicative of a comparison result between the first and second read signals; and a determination unit configured to determine an oscillation characteristic of the high-frequency oscillator from the comparative data.