Method of format savings via predictive correction of synchronization word
A method and system for providing format savings in data sectors. The method includes receiving a signal outputted from an analog-to-digital conversion circuit. The method further includes shifting a signal phase of the signal based at least upon a corrected phase at an output of a phase loop and a phase measured when the signal was digitally sampled by the analog-to-digital conversion circuit. The method also includes adjusting a gain of the signal based at least upon a current gain loop correction and a gain correction made when the signal was digitally sampled by the analog-to-digital conversion circuit. Additionally, the method includes adjusting the signal based at least upon an output of a current offset correction and an offset correction made when the signal was digitally sampled by the analog-to-digital conversion circuit. The method also includes outputting an adjusted signal to a sync mark detector.
1. A method, comprising:
receiving a signal outputted from an analog-to-digital conversion circuit; and
shifting a signal phase of the signal by a difference of i) a corrected phase at an output of a phase loop and ii) a phase measured when the signal was digitally sampled by the analog-to-digital conversion circuit;
adjusting a gain of the signal based at least upon i) a current gain loop correction and ii) a gain correction made when the signal was digitally sampled by the analog-to-digital conversion circuit;
adjusting the signal based at least upon i) an output of a current offset correction and ii) an offset correction made when the signal was digitally sampled by the analog-to-digital conversion circuit; and
outputting an adjusted signal to a sync mark detector.
2. The method of claim 1 , wherein adjusting a gain of the signal based at least upon i) a current gain loop correction and ii) a gain correction made when the signal was digitally sampled by the analog-to-digital conversion circuit further comprises:
adjusting a gain of the signal by a ratio of i) a current gain loop correction to ii) a gain correction made when the signal was digitally sampled by the analog-to-digital conversion circuit.
3. The method of claim 1 , wherein adjusting the signal based at least upon i) an output of a current offset correction and ii) an offset correction made when the signal was digitally sampled by the analog-to-digital conversion circuit further comprises:
adjusting the signal by a difference of i) an output of a current offset correction and ii) an offset correction made when the signal was digitally sampled by the analog-to-digital conversion circuit.
4. The method of claim 1 ,
wherein adjusting a gain of the signal based at least upon i) a current gain loop correction and ii) a gain correction made when the signal was digitally sampled by the analog-to-digital conversion circuit further comprises:
adjusting a gain of the signal by a ratio of i) a current gain loop correction to ii) a gain correction made when the signal was digitally sampled by the analog-to-digital conversion circuit; and
wherein adjusting the signal based at least upon i) an output of a current offset correction and ii) an offset correction made when the signal was digitally sampled by the analog-to-digital conversion circuit further comprises:
adjusting the signal by a difference of i) an output of a current offset correction and ii) an offset correction made when the signal was digitally sampled by the analog-to-digital conversion circuit.
5. The method of claim 4 , wherein adjusting a gain of the signal by a ratio of i) a current gain loop correction to ii) a gain correction made when the signal was digitally sampled by the analog-to-digital conversion circuit further comprises:
adjusting, after a delay, a gain of the signal by a ratio of i) a current gain loop correction to ii) a gain correction made when the signal was digitally sampled by the analog-to-digital conversion circuit.
6. The method of claim 1 , wherein, as a result of: shifting the signal phase of the signal by the difference of i) the corrected phase at the output of the phase loop and ii) the phase measured when the signal was digitally sampled by the analog-to-digital conversion circuit; adjusting the gain of the signal based at least upon i) the current gain loop correction and ii) the gain correction made when the signal was digitally sampled by the analog-to-digital conversion circuit; and adjusting the signal based at least upon i) the output of the current offset correction and ii) the offset correction made when the signal was digitally sampled by the analog-to-digital conversion circuit, the signal is corrected by utilizing information which was not applied when the signal was digitally sampled by the analog-to-digital conversion circuit.
7. The method of claim 1 , further comprising:
determining an initial rotation of incoming analog-to-digital data based upon a zero phase start calculation; and
determining a rate to de-rotate analog-to-digital samples based upon phase loop updates.
8. The method of claim 1 , further comprising:
receiving a selection to bypass an interpolator.
9. The method of claim 1 , wherein outputting an adjusted signal to a sync mark detector further comprises:
outputting a fractionally delayed adjusted signal to a sync mark detector.
10. The method of claim 1 , further comprising:
calculating a fractional delay; and
providing the fractional delay to a fractional delay filter.
11. The method of claim 1 , further comprising:
performing a phase prediction based upon a phase calculated by the phase loop and an updated phase provided to an interpolator; and
sending the phase prediction and an advance/retard direction to a quantize and saturate circuit.
12. The method of claim 11 , further comprising:
converting the phase prediction and the advance/retard direction to a phase delay; and
sending the phase delay to a fractional delay filter.
13. The method of claim 12 , wherein the fractional delay filter comprises an integer delay and a fractional delay.
14. A storage system, comprising:
an analog/digital conversion circuit;
a sync mark detector; and
a correction circuit, the correction circuit being coupled to the analog/digital conversion circuit and the sync mark detector, the correction circuit including a interpolator, a multiplier, and an offset adjustment means, wherein the correction circuit is configured to perform:
receiving a signal outputted from an analog-to-digital conversion circuit;
shifting a signal phase of the signal based at least upon i) a corrected phase at an output of a phase loop and ii) a phase measured when the signal was digitally sampled by the analog-to-digital conversion circuit;
adjusting a gain of the signal by a ratio of i) a current gain loop correction to ii) a gain correction made when the signal was digitally sampled by the analog-to-digital conversion circuit;
adjusting the signal based at least upon i) an output of a current offset correction and ii) an offset correction made when the signal was digitally sampled by the analog-to-digital conversion circuit; and
outputting an adjusted signal to the sync mark detector.
15. The storage system of claim 14 , wherein the storage system is implemented as a RAID (redundant array of independent storage devices) system.
16. The storage system of claim 14 , wherein the storage system comprises at least one hard disk drive.
17. A method, comprising:
receiving a signal outputted from an analog-to-digital conversion circuit;
shifting a signal phase of the signal based at least upon i) a corrected phase at an output of a phase loop and ii) a phase measured when the signal was digitally sampled by the analog-to-digital conversion circuit;
adjusting a gain of the signal based at least upon i) a current gain loop correction and ii) a gain correction made when the signal was digitally sampled by the analog-to-digital conversion circuit;
adjusting the signal by a difference of i) an output of a current offset correction and ii) an offset correction made when the signal was digitally sampled by the analog-to-digital conversion circuit;
performing a phase prediction based upon a phase calculated by the phase loop and an updated phase provided to an interpolator;
sending the phase prediction and an advance/retard direction to a quantize and saturate circuit;
converting the phase prediction and the advance/retard direction to a phase delay;
sending the phase delay to a fractional delay filter, wherein the fractional delay filter comprises an integer delay and a fractional delay; and
outputting an adjusted signal to a sync mark detector.
18. The method of claim 17 , further comprising:
receiving a selection to bypass an interpolator.
19. The storage system of claim 14 , wherein, as a result of: shifting the signal phase of the signal based at least upon i) the corrected phase at the output of the phase loop and ii) the phase measured when the signal was digitally sampled by the analog-to-digital conversion circuit; adjusting the gain of the signal by the ratio of i) the current gain loop correction to ii) the gain correction made when the signal was digitally sampled by the analog-to-digital conversion circuit; and adjusting the signal based at least upon i) the output of the current offset correction and ii) the offset correction made when the signal was digitally sampled by the analog-to-digital conversion circuit, the correction circuit corrects the signal by utilizing information which was not applied when the signal was digitally sampled by the analog-to-digital conversion circuit.
20. The method of claim 17 , wherein shifting a signal phase of the signal based at least upon i) a corrected phase at an output of a phase loop and ii) a phase measured when the signal was digitally sampled by the analog-to-digital conversion circuit further comprises:
shifting a signal phase of the signal by a difference of i) a corrected phase at an output of a phase loop and ii) a phase measured when the signal was digitally sampled by the analog-to-digital conversion circuit.