Abstract: The present invention relates broadly to a method of digitally filtering a signal, such as an audio signal, using a digital filter. The digital filter includes a plurality of neighbouring sample points broken into zones having different frequency content or frequency ranges. The zones adjacent one another may have neighbouring sample points in common. Generally each zone has at least same distinct frequencies compared with other zones. That is, the zones are roughly dependent on the frequency content. The invention in its preferred form involves combining values for two or more of the neighbouring sample points for select of the zones depending on its frequency content. The values are combined so as to provide a modified zone having substantially the same number of sample points as the select zone. The modified zones together provide a modified filter to be applied to the signal.

Abstract: The present invention relates broadly to a method of digitally filtering an audio signal by applying a composite audio filter. The composite audio filter may be obtained by applying one audio filter to another audio filter each having the same predetermined sample rate including neighboring sample points. The other audio filter may also include one or more intervening sample points between adjacent of its neighboring sample points. The one audio filter may be applied to the other audio filter at an adjusted sampling rate relative to the other audio filter. The adjusted sampling rate may be inversely proportional to the number of intervening sample points relative to the number of neighboring sample points for the other filter. The frequency response curve for the composite filter derived using the adjusted sampling rate may be more indicative of an idealized lowpass filter.

Abstract: The present invention relates broadly to a method of digitally filtering an audio signal at a predetermined sample rate by applying a composite audio filter derived at an increase sample rate. The composite audio filter is obtained by combining one audio filter with another audio filter at the increased sample rate. The sample rate of the audio filters may be increased from their predetermined to the increased sample rate using various weighting techniques. The composite filter may provide a frequency response curve with a corner frequency as it approaches the Nyquist frequency whereas the frequency response of a conventional filter (shown in broken line detail) is flat with no effect.

Abstract: The present invention relates broadly to a method of digitally filtering a signal, such as an audio signal, using a digital filter. The digital filter includes a plurality of neighbouring sample points broken into zones having different frequency content or frequency ranges. The zones adjacent one another may have neighbouring sample points in common. Generally each zone has at least same distinct frequencies compared with other zones. That is, the zones are roughly dependent on the frequency content. The invention in its preferred form involves combining values for two or more of the neighbouring sample points for select of the zones depending on its frequency content. The values are combined so as to provide a modified zone having substantially the same number of sample points as the select zone. The modified zones together provide a modified filter to be applied to the signal.

Abstract: A method of digitally filtering an audio signal using an adjusted audio filter. The adjusted audio filter is represented by an impulse response including a waveform in its time domain represented by a sine function of absolute values. A composite audio filter is derived from two adjusted audio filters although any number of filters may be used. The composite audio filter generally includes a bank of the filters which together define a frequency bandwidth representative of the audio signal or spectrum to be filtered. Also a bandpass filter is constructed by combining frequency responses for sine components of absolute values integrated from 0 to bpf and sine components of absolute values integrated from 1/bpf to 0. The frequency response may be the sum of the frequency responses for each of the filters used to create the composite bandpass filter.

Abstract: The present invention relates broadly to a method of digitally filtering an audio signal at a predetermined sample rate by applying a composite audio filter derived at an increase sample rate. The composite audio filter is obtained by combining one audio filter with another audio filter at the increased sample rate. The sample rate of the audio filters may be increased from their predetermined to the increased sample rate using various weighting techniques. The composite filter may provide a frequency response curve with a corner frequency as it approaches the Nyquist frequency whereas the frequency response of a conventional filter (shown in broken line detail) is flat with no effect.

Abstract: The present invention relates broadly to a method of digitally filtering an audio signal by applying a composite audio filter. The composite audio filter may be obtained by applying one audio filter to another audio filter each having the same predetermined sample rate including neighbouring sample points. The other audio filter may also include one or more intervening sample points between adjacent of its neighbouring sample points. The one audio filter may be applied to the other audio filter at an adjusted sampling rate relative to the other audio filter. The adjusted sampling rate may be inversely proportional to the number of intervening sample points relative to the number of neighbouring sample points for the other filter. The frequency response curve for the composite filter derived using the adjusted sampling rate may be more indicative of an idealised lowpass filter.

Abstract: A method of digitally filtering an audio signal using an adjusted audio filter. The adjusted audio filter is represented by an impulse response including a waveform in its time domain represented by a sine function of absolute values. A composite audio filter is derived from two adjusted audio filters although any number of filters may be used. The composite audio filter generally includes a bank of the filters which together define a frequency bandwidth representative of the audio signal or spectrum to be filtered. Also a bandpass filter is constructed by combining frequency responses for sine components of absolute values integrated from 0 to bpf and sine components of absolute values integrated from 1/bpf to 0. The frequency response may be the sum of the frequency responses for each of the filters used to create the composite bandpass filter.