Patent ID: 6353639
Filing Date: 2002-03-05
Classification: H03D,H04L,H04N

Abstract:
A filter configuration for a demodulated QAM signal, comprising:a first channel for a cosine demodulated QAM signal component; a second channel for a sine demodulated QAM signal component; a filter circuit for receiving the signal components, said filter circuit having transfer functions for the signal components, said transfer functions including terms in phase with the signal component of a respective one of said first an second channels and including terms phase-shifted by at least one of &pgr;/2 and âˆ’&pgr;/2 with respect to the signal component of said respective one of said first an second channels; said filter circuit including a cross branch having an output and an input for picking up signal portions from a respective other one of said first and second channels, the signal portions corresponding to the terms of the transfer functions phase-shifted by at least one of &pgr;/2 and âˆ’&pgr;/2; and a switch configuration having a first state and a second state, said switch configuration, when being in said first state, connecting said input of said cross branch to said first channel and said output of said cross branch to said second channel, said switch configuration, when being in said second state, connecting said input of said cross branch to said second channel and said output of said cross branch to said first channel.