Up-sampled filtering for servo demodulation
AssigneeMarvell International Ltd.
InventorsPantas Sutardja, Michael B. Madden
Life of this patent
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Abstract
An apparatus, method, and system for providing a fine adjustment for transducing head positioning in a hard disk drive (HDD). The apparatus, method, and system include reading a positioning error field wherein the resulting signal is a substantially sinusoidal position error signal (PES), filtering the PES to remove low frequencies and attenuate high frequencies, sample the filtered PES at a multiple of the channel frequency, filter the higher frequency harmonics, down sample the PES, and provide a signal proportional to the amplitude of the down sampled PES. This signal is the reference signal to the head positioning servo.
Claims35
An apparatus comprising:
- a continuous time filter (CTF) for receiving a substantially sinusoidal position error signal (PES) and transmitting a fundamental frequency while attenuating lower and higher frequencies of the PES to provide a filtered PES;
- an analog-to-digital converter (ADC) for sampling the filtered PES and providing a sampled PES;
- a digital filter, comprising a finite impulse response filter, for substantially eliminating a plurality of harmonic frequencies of the sampled PES;
- and
- a discrete Fourier transform (DFT) for providing an analog adjustment signal based on the filtered samples of the PES.
An apparatus comprising:
- means for filtering a substantially sinusoidal position error signal (PES) to pass the fundamental frequency and to attenuate lower and higher frequencies of the PES to provide a filtered PES;
- means for sampling the filtered PES to provide a sampled PES;
- means, comprising a finite impulse response filtering means, for substantially eliminating a plurality of harmonic frequencies of the sampled PES;
- and
- means for receiving the filtered samples of the PES and for providing an analog adjustment signal for positioning the transducing head.
A method comprising:
- producing a sinusoidal position error signal (PES);
- digitally filtering the PES with a digital filter comprising a finite impulse response filter to pass a fundamental frequency and to attenuate the lower and higher frequencies of the PES to provide a filtered PES;
- sampling the filtered PES to provide a sampled PES;
- substantially eliminating a plurality of harmonic frequencies of the filtered samples of the PES;
- and
- providing an analog adjustment signal.
Dependencies are inferred from the claim text.