Spectral analysis of a position error signal
View Patent ↗The present disclosure is directed to spectral analysis of a position error signal. In a particular embodiment, the method includes analyzing a spectral content of a position error signal. The method also includes comparing the spectral content to a threshold. Further, the method includes determining a result based on the comparing the spectral content to the threshold. In another particular embodiment, the spectral content of the position error signal is determined by performing a discrete fourier transform (DFT) on the error signal, determining a magnitude of the DFT output, and low pass filtering the magnitude.
1. A method comprising:
analyzing a spectral content of a position error signal;
comparing the spectral content to a threshold;
determining a result based on the comparing the spectral content to the threshold; and
detecting contact between a transducer and a data storage medium based on the result, wherein analyzing the spectral content further comprises analyzing at least one magnitude of at least one frequency spectra of the position error signal and wherein the contact between the transducer and the data storage medium is detected when the result indicates the at least one magnitude is greater than the threshold.
2. The method of claim 1 , further comprising filtering the at least one magnitude with a low pass filter.
3. The method of claim 1 , further comprising detecting contact between the transducer and the data storage medium when the result indicates the spectral content is greater than the threshold.
4. The method of claim 3 , wherein the method of detecting contact is performed continuously during operation of a data storage device.
5. The method of claim 3 , further comprising providing a real-time feedback signal in a data storage device to determine the result, wherein the real-time feedback signal monitors a transducer's operating performance.
6. The method of claim 5 , wherein the transducer's operating performance is a distance between the transducer and a data storage medium.
7. The method of claim 6 , wherein more than one frequency spectra are analyzed simultaneously.
8. The method of claim 1 , wherein the threshold is a fixed threshold.
9. The method of claim 1 , wherein the threshold is an adaptive threshold.
10. The method of claim 1 , wherein analyzing the spectral content further comprises performing at least one Discrete Fourier Transform (DFT) calculation on the position error signal.
11. The method of claim 10 , further comprising calculating the magnitudes of the at least one frequency spectra based on an output of the at least one DFT calculation.
12. The method of claim 10 , further comprising performing the DFT during a servo interrupt service routine (ISR).
13. The method of claim 1 , wherein the at least one frequency spectra is defined by at least one sine/cosine table and the position error signal is convolved with the at least one sine/cosine table to generate frequency components.
14. The method of claim 13 , wherein the position error samples are convolved with the at least one sine/cosine table to generate the frequency components during successive interrupt servo routines.
15. The method of claim 1 , wherein multiple frequencies are analyzed independently and a first independently monitored frequency is compared to a second independently monitored frequency.
16. A computer-readable medium having instructions for causing a processor to execute a method comprising:
analyzing a spectral content of a position error signal;
comparing the spectral content to a threshold;
determining a result based on comparing the spectral content to the threshold; and
detecting contact between a transducer and a data storage medium based on the result, wherein analyzing the spectral content further comprises analyzing at least one magnitude of at least one frequency spectra of the position error signal and wherein the contact between the transducer and the data storage medium is detected when the result indicates the at least one magnitude is greater than the threshold.
17. A computer-readable medium of claim 16 , wherein analyzing the spectral content further comprises analyzing at least one magnitude of at least one frequency spectra of the position error signal.
18. A device comprising:
a buffer for storing position error samples;
a processor programmed to
analyze at least one magnitude of at least one frequency spectra of the position error samples;
compare the at least one magnitude to a threshold;
determine a result based on comparing the at least one magnitude to the threshold; and
detect contact between a transducer and a data storage medium based on the result, wherein the contact between the transducer and the data storage medium is detected when the result indicates the at least one magnitude is greater than the threshold.
19. The device of claim 18 , further comprising:
a data storage medium;
a transducer movably disposed in relation to the data storage medium, wherein the transducer reads data from the data storage medium; and
wherein the result is monitored to determine contact between the transducer and the data storage medium.