US 2015/0317995 A1Published application

Multi-band signal processor for digital audio signals

AssigneeGN ReSound A/S

InventorsAalbert DE VRIES, Erik Cornelis Diederik VAN DER WERF

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Abstract

A method includes: processing the digital audio input signal to generate M delayed digital audio signal samples; converting the delayed digital audio signal samples to frequency domain representation in N number of frequency bands to compute respective signal spectrum values; determining respective signal level estimates; computing respective frequency domain gain coefficients based on the respective signal level estimates and band gain laws; transforming the frequency domain gain coefficients to time domain representation to produce M time-varying filter coefficients of a processing filter; convolving the M delayed digital audio signal samples with the time-varying filter coefficients to produce the processed digital output signal; and updating the delayed digital audio signal samples in accordance with a sample-by-sample or a predetermined block rate; wherein two of the signal spectrum values for at least two of the frequency bands are updated at different rates; and wherein M and N are positive integer numbers.

Claims15

Dependent claims

A multi-band signal processor comprising:

a signal input for receipt of a digital audio input signal;
a cascade of digital all-pass filters configured for receipt of the digital audio input signal and generation of M delayed digital audio signal samples at respective tapping nodes interposed between the digital all-pass filters;
a signal convolution processor configured for convolving the M delayed digital audio signal samples with M time-varying filter coefficients of a processing filter to produce a processed digital output signal;
a frequency domain transform processor configured for converting the M delayed digital audio signal samples to frequency domain representation to provide respective signal spectrum values in N number of frequency bands;
a level estimator configured to compute respective signal level estimates in the N number of frequency bands based on the respective signal spectrum values;
a processing gain calculator configured for computation of a frequency domain gain coefficient for each of the N number of frequency bands based on the respective signal level estimates and band gain laws;
and
an inverse frequency domain transform processor configured for conversion of the N frequency domain gain coefficients into the M time-varying filter coefficients of the processing filter;
wherein the frequency domain transform processor is configured to provide at least two of the signal spectrum values of at least two of the frequency bands at different band update rates;
and
wherein M is a positive integer number, and N is a positive integer number.

8 more elements

A method of processing a digital audio input signal to produce a processed digital output signal, comprising:

all-pass filtering the digital audio input signal through a cascade of digital all-pass filters to generate M delayed digital audio signal samples;
converting the M delayed digital audio signal samples to frequency domain representation in N number of frequency bands to compute respective signal spectrum values;
determining respective signal level estimates in the N number of frequency bands based on the signal spectrum values;
computing respective frequency domain gain coefficients for the N number of frequency bands based on the respective signal level estimates and band gain laws;
transforming the frequency domain gain coefficients to time domain representation to produce M time-varying filter coefficients of a processing filter;
convolving the M delayed digital audio signal samples with the M time-varying filter coefficients of the processing filter to produce the processed digital output signal;
and
updating the M delayed digital audio signal samples in accordance with a sample-by-sample rate or a predetermined block rate;
wherein at least two of the signal spectrum values for at least two of the N number of frequency bands are updated at different rates;
and
wherein M is a positive integer number, and N is a positive integer number.

8 more elements

Dependencies are inferred from the claim text.

Facts

Application: 14/269,773Filed 5 May 2014
Priority: DK PA 2014 702691 May 2014
Published: 5 Nov 2015
Term ends: Not estimatedThe source records don’t support an estimate.

Classification10 codes

G10L 21/0364
By changing the amplitude: for improving intelligibility
G10L 19/02
Speech or audio signals analysis-synthesis techniques for redundancy reduction, e.g. in vocoders; Coding or decoding of speech or audio signals,…:…
G10L 19/265
Pre-filtering or post-filtering: pre-filtering, e.g. high frequency emphasis prior to encoding
H04R 25/356
Using translation techniques: amplitude, e.g. amplitude shift or compression