Detecting LTO Servo Patterns on Perpendicular Recorded Media

1 . A servo processing circuit, comprising:

a correlation filter operable to:

receive a first signal as input;

correlate the first signal with a reference signal; and

produce a second signal as output, wherein the second signal indicates a correlation between the first signal and the reference signal; and

a Lagrange interpolator peak detector coupled to the correlation filter and operable to:

receive the second signal as input;

detect one or more peaks in the second signal; and

produce a third signal as output, wherein the third signal indicates one or more peak locations of the peaks in the second signal.

2 . The servo processing circuit recited in claim 1 , further comprising:

a low pass filter operable to:

receive a fourth signal as input, wherein the fourth signal represents a perpendicular recorded servo pattern comprising a plurality of stripes; and

produce a fifth signal as output by applying low pass filter to the fourth signal; and

an analog-to-digital converter coupled to the low pass filter and the correlation filter and operable to:

receive the fifth signal as input; and

produce the first signal by converting the fifth signal from analog form to digital form.

3 . The servo processing circuit recited in claim 2 , further comprising a servo pattern de-formatter coupled to the Lagrange interpolator peak detector and operable to:

receive the third as input;

determine one or more stripe locations of the stripes of the fourth signal based on the peak locations; and

produce a sixth signal as output, wherein the sixth signal indicates P distance, S distance, manufacturing data, LPOS, and Servo Frame.

4 . The servo processing circuit recited in claim 1 , wherein the correlation filter is a finite impulse response filter.

5 . The servo processing circuit recited in claim 1 , wherein:

the correlation filter has one or more filter coefficients;

each one of the filter coefficients has a static, predetermined value; and

the values of the filter coefficients correspond to the reference signal.

6 . The servo processing circuit recited in claim 5 , wherein to correlate the first signal with a reference signal, the correlation filter is operable to:

delay the first signal one or more sample times, wherein each one of the delays corresponds to one of the filter coefficients;

at each one of the delays, multiply the first signal by the corresponding filter coefficient; and

add one or more multiplication results corresponding to all the delays to obtain the second signal.

7 . A method, comprising:

receiving, at a correlation filter, a first signal as input;

correlating, by the correlation filter, the first signal with a reference signal;

producing, by the correlation filter, a second signal as output, wherein the second signal indicates the correlation between the first signal and the reference signal;

receiving, at a Lagrange interpolator peak detector coupled to the correlation filter, the second signal as input;

detecting, by the Lagrange interpolator peak detector, one or more peaks in the second signal; and

producing, Lagrange interpolator peak detector, a third signal as output, wherein the third signal indicates one or more peak locations of the peaks in the second signal.

8 . The method recited in claim 7 , further comprising:

receiving, at a low pass filter, a fourth signal as input, wherein the fourth signal represents a perpendicular recorded servo pattern comprising a plurality of stripes;

producing, by the low pass filter, a fifth signal as output by applying low pass filter to the fourth signal;

receiving, at an analog-to-digital converter coupled to the low pass filter and the correlation filter, the fifth signal as input; and

producing, by the analog-to-digital converter, the first signal by converting the fifth signal from analog form to digital form.

9 . The method recited in claim 8 , further comprising:

receiving, at a servo pattern de-formatter coupled to the Lagrange interpolator peak detector, the third as input;

determining, by the servo pattern de-formatter, one or more stripe locations of the stripes of the fourth signal based on the peak locations; and

producing, by the servo pattern de-formatter, a sixth signal as output, wherein the sixth signal indicates P distance, S distance, manufacturing data, LPOS, and Servo Frame.

10 . The method recited in claim 7 , wherein the correlation filter is a finite impulse response filter.

11 . The method recited in claim 7 , wherein:

the correlation filter has one or more filter coefficients;

each one of the filter coefficients has a static, predetermined value; and

the values of the filter coefficients correspond to the reference signal.

12 . The method recited in claim 11 , wherein correlating the first signal with a reference signal comprises:

delaying the first signal one or more sample times, wherein each one of the delays corresponds to one of the filter coefficients;

at each one of the delays, multiplying the first signal by the corresponding filter coefficient; and

adding one or more multiplication results corresponding to all the delays to obtain the second signal.