Patent ID: 6191648
Filing Date: 2001-02-20
Classification: H03H,H03K

Abstract:
An apparatus including a switched-capacitor cosine filter circuit, comprising:inverse and noninverse signal input terminals for conveying inverse and noninverse phases of a differential input signal, respectively;a differential amplifier with first and second input terminals and at least one output terminal that in response to first and second input signals provide at least one output signal, respectively;a switched-capacitor feedback circuit, coupled between said at least one output terminal and at least one of said first and second input terminals, that in response to a plurality of control signals capacitively couples each one of said at least one output terminal individually to a respective one of said at least one of said first and second input terminals; anda switched-capacitor input circuit, coupled between said inverse and noninverse signal input terminals and said at least one of said first and second input terminals, that in response to a first portion of said plurality of control signals alternately capacitively couples said inverse and noninverse signal input terminals and said at least one of said first and second input terminals;whereinduring a first state of said plurality of control signals, said switched-capacitor cosine filter circuit samples said inverse and noninverse differential input signal phases as a noninverting integrator circuit, andduring a second state of said plurality of control signals, said switched-capacitor cosine filter circuit samples said inverse and noninverse differential input signal phases as an inverting integrator circuit.