Patent ID: 7688059
Filing Date: 2010-03-30
Classification: H03H

Abstract:
1. A filter characteristic frequency adjusting apparatus comprising: a filter: a test signal generation unit for receiving a reference signal, and generating a test signal to be supplied to said filter when adjusting a frequency characteristic of said filter, such that the filter outputs a predetermined filter output signal when the test signal is supplied to the filter; a phase shift unit for phase-shifting the test signal generated by the test signal generation unit so that a predetermined phase difference is generated between the phase of the test signal and the phase of said predetermined filter output signal, based on a phase characteristic of the filter and a frequency of the test signal; and a control signal generation unit for receiving the predetermined filter output signal and the phase-shifted test signal and for generating a control signal which controls a frequency characteristic of the filter, wherein said control signal generation unit comprises: a logic unit for generating the control signal by using the output from the phase comparator and the output from the second comparator, wherein said logic unit comprises: