Patent ID: 6515466
Filing Date: 2003-02-04
Classification: H03D

Abstract:
A phase comparator for calculating the phase difference between a test wave form and an output wave form in a disk drive to perform an open loop gain adjustment, comprising:a phase converter for delaying the test wave form for a specific time based on the frequency thereof, wherein the test wave form is a sinusoidal wave and the output wave form is orthogonal to the test wave form; a first multiplier electrically coupled to the phase converter for performing a first operation by multiplying the delayed test wave form with the output wave form; a first integrator electrically coupled to the first multiplier for integrating the result of the first operation for a period to generate a first weighted value; a second multiplier for performing a second operation by multiplying the test wave form with the output wave form; a second integrator electrically coupled to the second multiplier for integrating the result of the second operation for the same period to generate a second weighted value; and a phase angle calculator electrically coupled to the first integrator and the second integrator for receiving the first weighted value and the second weighted value and then outputting a value representing the phase difference between the test wave form and the output wave form based on a ratio of the first weighted value to the second weighted value, wherein the open loop gain adjustment forces the disk drive to have a consistent system bandwidth.