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, having
- a first path (20), in which the audio signal is routed essentially unchanged to an output summing stage (12), and
- a second path (22), which has a plurality of series-connected filter stages (3, 6, 7), where the audio signal is input into a first filter stage (3) from the series-connected filter stages and is routed via the series-connected filter stages to the output summing stage (12), and where the second path has a plurality of subsidiary paths via which the audio signal is supplied directly to further filter stages (6, 7) from the series-connected filter stages, and
- where at least one of the filter stages is adjustable and the adjustment of one filter stage affects the operation of at least one other filter stage.
The filter circuit as claimed in one of the preceding claims, characterized in that the filter stages comprise a control filter (3), a modified bandpass filter (6) and a modified universal filter (7) which are connected in series in this order.
The filter circuit as claimed in one of the preceding claims, characterized in that the modified universal filter (7) has a universal filter core (14) which comprises a low-pass filter (OP71), a bandpass filter (OP72) and a high-pass filter (OP73).
The filter circuit as claimed in one of the preceding claims, characterized in that the second path (22) has a regulatable amplifier (1) connected upstream of it.
The filter circuit as claimed in one of the preceding claims, characterized in that the second path (22) has a further subsidiary path, which contains a treble and harmonic filter (4) whose input receives the audio signal and whose output is connected to the output summing stage (12).
A method for processing an audio signal, in which the audio signal is processed using a first filter function in order to produce a first processed audio signal, the audio signal and the first processed audio signal are processed using a second filter function in order to produce a second processed audio:
- signal, the audio signal and the second processed audio signal are processed using a third filter function in order to produce a third processed audio signal, and the third processed audio signal and the essentially unprocessed audio signal are summed 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.
Dependencies are inferred from the claim text.