US 2006/0233286 A1 · Asynchronous servo RRO detection employing interpolation

Abstract

A repeatable read-out (RRO) detector employs one or more digital interpolators to interpolate asynchronous sample values that represent RRO data. The asynchronous sample values are read from a recording medium and generated by an A/D converter at a symbol rate, and the interpolators generate interpolated samples at at least one time in between the asynchronous sample value times. Each interpolated sample corresponding to some phase relative to that of the sample values generated by the A/D converter. The RRO detector receives 1) the asynchronous samples at symbol rate and 2) the interpolated samples to efficiently detect the encoded RRO data. An RRO address mark indicates when detection of encoded RRO data starts, and is employed to select those samples suitable for RRO data detection. Detection of the RRO address mark employs peak detection among filtered asynchronous and interpolated samples. The process of peak detection adjusts the current best phase for sample selection. When the RRO address mark is found, the corresponding best phase corresponds to either asynchronous sampled values or interpolated samples that are subsequently selected for RRO data detection, termed best samples. Once the best phase is selected, the RRO data detector uses that information along with RRO encoding constraints to decode the encoded RRO data from the best samples.

Claims21

Dependent claims

An apparatus for detecting data in samples read from a recording channel, the apparatus comprising:

an interpolator adapted to generate one or more interpolated samples from sets of read samples, wherein each interpolated sample has a corresponding phase relative to one of the associated sets of read samples;
and
at least one filter adapted to generate output values from either i) a read sample or ii) an interpolated sample at a given phase, wherein the filter has a filter response based on a target partial response of the recording channel;
a detector adapted to detect one or more peaks within the filter output values, wherein:
1) each peak is based on data values of the sample corresponding to the filter output values,
2) as each peak is detected, the detector adjusts a best phase value based on the given phase of the sample corresponding to the peak, and,
3) when a predetermined number of peaks are found, the detector provides the corresponding best phase value to select samples from among the read samples and the one or more interpolated samples for data detection.

4 more elements

Dependencies are inferred from the claim text.

Asynchronous servo RRO detection employing interpolation

Life of this patent

Asynchronous servo RRO detection employing interpolation

Life of this patent

Abstract

Claims21