Patent ID: 7944286
Filing Date: 2011-05-17
Classification: H03J

Abstract:
1. A filter tuning system comprising: a time constant detector configured to detect a time constant of a filter based on an integral value of a reference input signal using a integrator when the time constant of the filter changes according to a variation of a manufacturing process or a temperature, the integrator including a capacitor changing according to a variation of the time constant of the filter, the capacitor included in the integrator being located in the same environment as the filter; a comparator configured to compare the detected time constant with a reference value; and a calibration unit configured to compensate the time constant of the filter using a binary search algorithm based on the comparison result until an error between the time constant and the reference value is reduced within an acceptable range, wherein the calibration unit decreases the time constant by a unit of a calibration interval when the comparison result corresponds to a first logic value, the calibration unit increases the time constant by a unit of the calibration interval when the comparison result corresponds to a second logic value, and the calibration unit decreases a calibration interval for the next repetition by half of the calibration interval for a current repetition when repeating the increasing or decreasing of the time constant.