Patent ID: 6552604
Filing Date: 2003-04-22
Classification: H03H

Abstract:
A notch filter circuit comprising:a first stage circuit comprising a first stage input and a first stage output terminal, said first stage circuit summing a filter input signal with a filter output signal to form a summation signal; and a second stage circuit having a second stage output terminal and comprising; a first tee network electrically coupled to said first stage input and low-pass filtering said filter input signal to form a first tee output signal; a second tee network electrically coupled to said first stage output terminal and high-pass filtering said summation signal to form a second tee output signal; and a first multiplying digital-to-analog converter electrically coupled to said first tee network and said second tee network, said first multiplying digital-to-analog converter modifying gain of said second tee network in response to a gain signal to form a corrected second tee network signal; said second stage circuit summing said first tee output signal with said corrected second tee output signal to form said filter output signal.