Determining a reference waveform used by a correlator in a servo channel
AssigneeInternational Business Machines Corporation
InventorsGiovanni CHERUBINI, Robert Allen HUTCHINS, Jens JELITTO
Life of this patent
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Abstract
Provided are a method, servo channel, and tape drive for determining a reference waveform used by a correlator in a servo channel. Sequences of servo signal samples are provided from read servo signals read from a servo pattern on a recording medium. A determination is made of a reference waveform based on the sequences of servo signal samples and the reference waveform is forwarded. Interpolated servo signals are generated. The interpolated servo signal samples and the forwarded reference waveform are received to generate correlation output samples. Position and velocity information are calculated from the correlation output samples.
Claims11
1-9. (canceled)
A method implemented in a servo channel, comprising:
- providing sequences of servo signal samples from read servo signals read from a servo pattern on a recording medium;
- determine a reference waveform based on the sequences of servo signal samples;
- forwarding the reference waveform;
- generating interpolated servo signal samples:
- receiving the interpolated servo signal samples and the forwarded reference waveform to generate correlation output samples;
- calculating position and velocity information from the correlation output samples.
The method of claim 1, wherein the determining and forwarding of the reference waveform comprises:
- measuring distances between peaks within dibits in the read servo signals;
- selecting a reference waveform from a predetermined set of waveforms based on the measured distance between the peaks;
- forwarding the selected reference waveform from the predetermined set;
- and
- processing sequences of servo signal samples, following the forwarding of the reference waveform from the predetermined set, to generate an estimated reference waveform;
- and
- forwarding the estimated reference waveform, wherein the selected reference waveform and the estimated reference waveform are used to generate correlation output samples.
The method of claim 9, wherein processing the sequences of servo signal samples to generate the estimated reference waveform comprises averaging the sequences of servo signals from consecutive servo bursts and wherein the measured distance comprises a distance between a positive peak and a negative peak of a dibit.
The method of claim 9, further comprising:
- initializing a counter, wherein the determining of the reference waveform is performed in response to initializing the counter value;
- incrementing the counter in response to a clock cycle;
- generate a new estimated reference waveform in response to the counter reaching a counter maximum value;
- and
- forwarding the new estimated reference waveform to the correlator.
17-22. (canceled)
Dependencies are inferred from the claim text.