US 10,601,617 B1 · Position error signal burst demodulation

Abstract

A method may generate a demodulated sine component for a sequence of samples of a servo burst window of a position error signal using a sine weight look up table and generate a demodulated cosine component for the sequence of samples of the servo burst window of the position error signal using a cosine weight look up table. The sine weight and the cosine weight look up tables may have indexes representing a phase range. The method may generate a demodulated phase component signal and a demodulated amplitude component signal for the sequence of samples of the servo burst window of the position error signal based on the demodulated sine component and the demodulated cosine component using a Coordinate Rotation Digital Computer at least in part by iteratively rotating a vector based on the demodulated sine component and the demodulated cosine component and summing angular changes in the vector.

Claims18

Dependent claims

An apparatus comprising:

a circuit having a CORDIC (Coordinate Rotation Digital Computer), the circuit configured to:
receive a plurality of samples of a continuous time input signal corresponding to a servo burst window of a position error signal;
generate a sequence of digitized samples of the servo burst window of the position error signal based on the continuous time input signal;
determine a phase offset based on a timing signal, a step size and a number of solutions;
determine demodulated sine and cosine values using cosine and sine weight LUTs based on the digitized samples, the phase offset, a burst frequency, and a burst length component based at least in part on the digitized samples;
generate a demodulated phase component signal and a demodulated amplitude component signal based on a based on a phase direction value, a number of iterations value, the demodulated cosine value and the demodulated sine value using the CORDIC;
and
the circuit having one or more outputs to provide the demodulated phase component signal and the demodulated amplitude component signal to a servo control system.

5 more elements

A method comprising:

generating a demodulated sine component for a sequence of samples of a servo burst window of a position error signal using a sine weight look up table;
generating a demodulated cosine component for the sequence of samples of the servo burst window of the position error signal using a cosine weight look up table, the sine weight look up table and the cosine weight look up table having indexes representing a phase range;
and
generating a demodulated phase component signal and a demodulated amplitude component signal for the sequence of samples of the servo burst window of the position error signal based on the demodulated sine component and the demodulated cosine component using a CORDIC (COordinate Rotation DIgital Computer) at least in part by:
iteratively rotating a vector based on the demodulated sine component and the demodulated cosine component;
and
determining an angular change in the vector resulting from the iterative rotating of the vector.

4 more elements

Dependencies are inferred from the claim text.

Position error signal burst demodulation

Life of this patent

Position error signal burst demodulation

Life of this patent

Abstract

Claims18