Patent ID: 7352872
Filing Date: 2008-04-01
Classification: H03G

Abstract:
1. A filter circuit for processing an audio signal comprising: a first path, in which the audio signal is routed essentially unchanged to an output summing stage, and a second path having a plurality of series-connected filter stages, where the audio signal is input into a first filter stage of the series-connected filter stages and is routed via the series-connected filter stages to the output summing stage, said plural filter stages comprising a control filter, a modified bandpass filter and a modified universal filter which are connected in series in this order, a third path having a plurality of auxiliary paths via which the audio signal is supplied directly to at least one other of the series-connected filter stages, wherein a first auxiliary path is supplied to said control filter, a second auxiliary path is combined with an output signal of said control filter, a third auxiliary path is supplied to said modified universal filter, and a fourth auxiliary path is supplied to said output summing stage, and where at least one of the filter stages is adjustable and the adjustment of one filter stage affects the operation of the at least one other of the series-connected filter stages.