Filter circuit and method for processing an audio signal
AssigneeSPL Electronics GmbH
InventorsWolfgang Neumann, Hermann Gier
Life of this patent
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Abstract
The invention relates to a filter circuit for processing an audio signal, comprising a first branch in which the audio signal is guided in an essentially unchanged state to an output summation stage, and a second branch comprising several series-connected filter stages. The audio signal is inputted into a first filter stage of the series-connected filter stages and guided via said stages to an output summation stage. The second branch comprises several secondary branches via which the audio signal is directly guided to further filter stages of the series-connected filter stages. At least one of the filter stages is adjustable and adjusting one filter stage has an impact on the function of another filter stage.
Claims23
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.
A method for processing an audio signal comprising the steps of:
- amplifying the audio signal,
- processing, the amplified audio signal using a first filter function in order to produce a first processed audio signal said first filter function providing control filtering,
- processing the amplified audio signal and the first processed audio signal using a second filter function in order to produce a second processed audio signal said second filter function providing bandpass filtering,
- processing the amplified audio signal and the second processed audio signal using a third filter function in order to produce a third processed audio signal filter function providing universal filtering, and
- summing the third processed audio signal, the amplified audio signal, and an essentially unprocessed audio signal in order to produce an audio output signal,
- where at least one of the filter functions is adjustable and the adjustment of one filter function affects another filter function.
A filter circuit comprising:
- a first path adaptable to receive an input audio signal in which the input audio signal is routed essentially unchanged to an output summing stage;
- and
- a second path adaptable to amplify said input audio signal and supply an amplified audio signal to a plurality of subsidiary paths,
- a first plural subsidiary path having a plurality of series-connected filter stages, where the amplified 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 second plural subsidiary path supplied to said control filter,
- a third plural subsidiary path combined to an output of said control filter,
- a fourth plural subsidiary path supplied to said modified universal filter, and
- a fifth plural subsidiary path supplied to said output summing stage
- wherein 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.
Dependencies are inferred from the claim text.