Methods and systems for estimating time corresponding to peak signal amplitude
View Patent ↗Various systems and methods for peak signal detection. As one example, a method for peak signal detection that includes receiving a signal is disclosed. The received signal includes a signal region where the signal is increasing in amplitude, another signal region where the signal is decreasing in amplitude, and a transitional signal region coupling the first two signal regions. In some cases, the transitional region is of zero duration and the signal transitions directly from the increasing region to the decreasing region. The method further include calculating a distance between the signal region of increasing amplitude and the signal region of decreasing amplitude, and determining a peak of the received signal that is one half the distance from the signal region of increasing amplitude.
1. A system for detecting a peak signal location, the system comprising:
a spiral entry locator circuit operable to receive a signal that includes a first signal region increasing in amplitude preceding a transitional signal region, and to detect an entry region corresponding to an entry cross-over of a spiral reference pattern; and
a spiral exit locator circuit that includes a sample number and is operable to:
receive the signal that includes a second region of decreasing amplitude succeeding the transitional signal region,
continuously detect an exit region corresponding to an exit cross-over of the spiral reference pattern,
store a first sequence of samples corresponding to the sample number from the entry region of the spiral reference pattern, and
store a second sequence of samples corresponding to the sample number from the exit region of the spiral reference pattern;
a comparator operable to compare the first sequence of samples with the second sequence of samples on a sample by sample basis and in reverse order.
2. The system of claim 1 , wherein the comparator is further operable to determine a minimum difference between a sample from the first sequence of samples and a sample from the second sequence of samples, the system further comprising:
a location calculator operable to determine a
location corresponding to the determined minimum distance.
3. The system of claim 2 , wherein determining the minimum difference between the sample from the first sequence of samples and the sample from the second sequence of samples includes:
determining a first slope associated with the first signal region;
determining a second slope associated with the second signal region; and
determining an intercept between a first line exhibiting the first slope and a second line exhibiting the second slope, wherein the intercept corresponds to a peak of the signal.
4. The system of claim 2 , wherein the system is implemented as part of a hard disk drive, and wherein the system further comprises:
a storage medium that includes the spiral reference pattern;
a head assembly disposed in relation to the storage medium; and
wherein receiving the signal is generated by traversing the storage medium by the head assembly along a traversal path, wherein the traversal path crosses the spiral reference pattern at an angle greater than zero, wherein the first signal region occurs in relation to an increasing cross-over with the spiral reference pattern, wherein the second signal region occurs in relation to a decreasing cross-over with spiral reference pattern, and wherein the transitional signal region occurs in relation to a substantially constant cross-over with the spiral reference pattern.
5. The system of claim 4 , wherein the system further comprises:
a digital interpolator circuit operable to interpolate the signal to yield phase aligned samples from the first signal region with samples from the second signal region.
6. The system of claim 4 , wherein the angle at which the traversal path crosses the spiral reference pattern is programmable.
7. The system of claim 1 , wherein the first signal region is substantially symmetric with the second signal region.
8. The system of claim 1 , wherein an average amplitude of the transitional signal region is greater than an average amplitude of the first signal region.
9. A system for determining a peak signal location, the system comprising:
a first circuit operable to:
receive a signal that includes a first signal region and a second signal region, and wherein the first signal region exhibits an increasing amplitude and the second signal region exhibits a decreasing amplitude, and
identify the first signal region; and
a second circuit operable to:
receive the signal;
store a first sequence of samples corresponding to the first signal region; and
store a second sequence of samples corresponding to the second signal region;
a comparator operable to compare the first sequence of samples with the second sequence of samples on a sample by sample basis to determine a minimum difference between one of the first sequence of samples and one of the second sequence of samples.
10. The system of claim 9 , wherein comparing the first sequence of samples with the second sequence of samples on a sample by sample basis is done in reverse sample order.
11. The system of claim 9 , wherein the signal is a spiral reference pattern, the system further comprising:
a location calculator operable to determine a location corresponding to a peak of the spiral reference pattern, wherein the peak of the spiral reference pattern is defined as half way between the one of the first sequence of samples and the one of the second sequence of samples.
12. The system of claim 11 , wherein determining the minimum difference between one of the first sequence of samples and one of the second sequence of samples includes:
determining a first slope associated with the first signal region;
determining a second slope associated with the second signal region; and
determining an intercept between a first line exhibiting the first slope and a second line exhibiting the second slope, wherein the intercept corresponds to a peak of the signal.
13. The system of claim 9 , wherein the first signal region is substantially symmetric with the second signal region.
14. The system of claim 9 , wherein an average amplitude of the first signal region is approximately equal to an average amplitude of the second signal region.
15. The system of claim 9 , wherein the first signal region and the second signal region are joined by a transitional signal region.
16. The system of claim 9 , wherein the signal is a spiral reference pattern, wherein the system is implemented as part of a hard disk drive, and wherein the system further comprises:
a storage medium that includes the spiral reference pattern;
a head assembly disposed in relation to the storage medium; and
wherein receiving the signal is generated by traversing the storage medium by the head assembly along a traversal path, wherein the traversal path crosses the spiral reference pattern at an angle greater than zero, wherein the first signal region occurs in relation to an increasing cross-over with the spiral reference pattern, wherein the second signal region occurs in relation to a decreasing cross-over with spiral reference pattern, and wherein the transitional signal region occurs in relation to a substantially constant cross-over with the spiral reference pattern.
17. A system for writing servo data, the system comprising:
a spiral entry locator circuit, wherein the spiral entry locator circuit is operable to detect an entry region corresponding to a first cross-over of a spiral reference pattern;
a spiral exit locator circuit, wherein the spiral exit locator circuit includes a sample number, and wherein the spiral exit locator circuit is operable to:
detect an exit region corresponding to a second cross-over of the spiral reference pattern,
store a first sequence of samples corresponding to the sample number from the entry region of the spiral reference pattern, and
store a second sequence of samples corresponding to the sample number from the exit region of the spiral reference pattern;
a comparator, wherein the comparator is operable to compare the first sequence of samples with the second sequence of samples on a sample by sample basis and in reverse order and to determine a minimum difference between a sample from the first sequence of samples and a sample from the second sequence of samples; and
a location calculator, wherein the location calculator is operable to determine a location corresponding to the determined minimum distance.
18. The system of claim 17 , wherein the system further comprises:
a storage medium, wherein the storage medium includes the spiral reference pattern;
wherein the spiral entry locator circuit receives a signal derived from a head assembly traversing the storage medium along a traversal path, wherein the traversal path crosses the spiral reference pattern at an angle greater than zero, and wherein the entry region corresponds to a region where the head is increasingly crossing over the spiral reference pattern; and
wherein the spiral exit locator circuit receives the signal derived from the head traversing the storage medium along the traversal path, and wherein the exit region corresponds to a region where the head is decreasingly crossing over the spiral reference pattern.
19. The system of claim 17 , wherein the spiral entry locator circuit includes a notch filter and a band pass filter.
20. The system of claim 19 , wherein the notch filter includes the following coefficients: 1, 0, 0, 0, −1; and wherein the band pass filter includes the following coefficients: 1, 1, −1, −1, 1, 1, −1, −1.
21. The system of claim 17 , wherein the system is implemented as part of a hard disk drive.
22. The system of claim 17 , wherein determining the minimum difference between the sample from the first sequence of samples and the sample from the second sequence of samples includes:
determining a first slope associated with the first signal region;
determining a second slope associated with the second signal region; and
determining an intercept between a first line exhibiting the first slope and a second line exhibiting the second slope, wherein the intercept corresponds to a peak of the signal.
23. The system of claim 17 , wherein the entry region is substantially symmetric with the exit region.
24. The system of claim 17 , wherein a transitional region extends between the entry region and the exit region, and wherein an average amplitude of the transitional signal region is greater than an average amplitude of the entry region.
25. The system of claim 17 , wherein the system further comprises:
a digital interpolator circuit operable to interpolate the signal to yield phase aligned samples from the entry region with samples from the exit region.