Patent ID: 8000047

Claim:
A magnetic head or magnetic disk testing apparatus for measuring characteristics of a magnetic head or a magnetic disk, the magnetic head or magnetic disk testing apparatus comprising: a servo signal detector for reading a servo signal written in each sector of the magnetic disk, through the magnetic head; and a servo controller including a head detection and positioning unit for detecting and positioning a position of the magnetic head on the magnetic disk based on the servo signal detector, wherein the servo signal detector includes an analog to digital conversion unit for quantizing the servo signal, and an analysis unit for performing harmonic analysis of the servo signal quantized by the analog to digital conversion unit, wherein the quantized servo signal has n (n is a power of 2) pieces of data, wherein the analysis unit starts operation based on an operation start signal generated by a timing signal according to a sector signal, wherein the analog to digital conversion unit quantizes the n (n is a power of 2) servo signals based on the timing signal, wherein the servo signal detector further includes a window function operation unit for applying a window function to the quantized servo signal, and wherein the analysis unit applies FFT or DFT operation to the n pieces of windowed data.