Baseline popping noise detection circuit
AssigneeBroadcom Corporation, a California Corporation
InventorBahjat Zafer
Life of this patent
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Abstract
A technique to detect head instability by monitoring for a baseline popping (BLP) noise effect on demodulation bursts read from a disk. In one technique, a digital filter is employed as a moving average filter so that the filtering of the bursts has a zero output from the filter if only the bursts are present. However, when a BLP event occurs, the noise effect causes a non-zero output from the filter. A threshold value is set and when the output of the filter exceeds the threshold value, a BLP indication is noted. Although various filters may be used, in one technique, a filter suitable for use in detecting thermal asperity defects is used for the BLP detection filter.
Claims20
An apparatus comprising:
- a first detection module to detect a signal from a storage medium;
- and
- a second detection module coupled to receive the signal from the first detection module and to filter the signal by use of a thermal asperity filter to detect if a baseline popping (BLP) event has occurred.
An apparatus comprising:
- a servo detection module to detect demodulation bursts of a servo signal from a disk;
- and
- a baseline popping (BLP) detection module coupled to receive the demodulation bursts from the servo detection module and to process the demodulation bursts to detect if noise caused by a BLP event is present.
A method comprising:
- detecting demodulation bursts of a servo signal from a disk;
- and
- detecting occurrence of baseline popping (BLP) noise by processing the demodulation bursts to identify a substantially rapid rise of the demodulation bursts followed by exponential decay.
Dependencies are inferred from the claim text.