Apparatus and method for generating a bandwidth extended signal

Patent metadata

Field	Value
Publication number	US-RE50639-E
Application number	US-202318518339-A
Country	US
Kind code	E1
Filing date	Nov 22, 2023
Priority date	Jul 11, 2008
Publication date	Oct 14, 2025
Grant date	Oct 14, 2025

Abstract

An apparatus for generating a bandwidth extended signal from an input signal includes a patch generator and a combiner. The input signal is represented for first and second bands by first and second resolution data, respectively, the second resolution being lower than the first. The patch generator generates first and second patches from the first band of the input signal according to first and second patching algorithms, respectively. A spectral density of the second patch generated using the second patching algorithm is higher than a spectral density of a first patch generated using the first patching algorithm. The combiner combines both patches and the first band of the input signal to obtain the bandwidth extended signal. The apparatus scales the input signal according to the first and second patching algorithms or scales the first and second patches, so that the bandwidth extended signal fulfills a spectral envelope criterion.

First claim

The invention claimed is:

1. An apparatus for generating a bandwidth extended signal from an input signal, wherein the input signal is represented, for a first band by a first resolution data, and for a second band by a second resolution data, the second resolution being lower than the first resolution, the apparatus comprising:
a patch generator configured to generate a first patch from the first band of the input signal according to a first patching algorithm and configured to generate a second patch from the first band of the input signal according to a second patching algorithm, wherein a spectral density of the second patch generated according to the second patching algorithm is higher than a spectral density of the first patch generated according to the first patching algorithm; and a combiner configured to combine the first patch, the second patch and the first band of the input signal to acquire the bandwidth extended signal, wherein the apparatus for generating a bandwidth extended signal is configured to scale the input signal according to the first patching algorithm and according to the second patching algorithm or to scale the first patch and the second patch, or to scale only one of the first and second patches to obtain a scaled patch, to then combine the scaled patch and a non-scaled patch from the first and second patches to obtain combined patches, and to then scale the combined patches before combining the combined patches with the first band of the input signal, so that the bandwidth extended signal fulfills a spectral envelope criterion.

2. The apparatus according to claim 1 , wherein the first patching algorithm is a harmonic patching algorithm and the patch generator is configured to generate the first patch, so that only frequencies that are integer multiples of frequencies of the first band of the input signal are comprised by the first patch.

3. The apparatus according to claim 1 , wherein the second patching algorithm is a mixing patching algorithm and the patch generator is configured to generate the second patch, so that the second patch comprises frequencies that are integer multiples of frequencies of the first band of the input signal and comprises frequencies that are not integer multiples of frequencies of the first band of the input signal.

4. The apparatus according to claim 1 , wherein a lower cut-off frequency of the first patch is equal to a lower cut-off frequency of the second patch, and wherein an upper cut-off frequency of the first patch is equal to an upper cut-off frequency of the second patch.

5. The apparatus according to claim 1 , comprising a phase vocoder configured to generate the first patch according to the first patching algorithm.

6. The apparatus according to claim 1 , comprising an amplitude clipper configured to generate the second patch according to the second patching algorithm by clipping the first band of the input signal.

7. The apparatus according to claim 1 , comprising a spectral line selector configured to select a plurality of frequency lines of the second patch to acquire a modified second patch, wherein a frequency line is selected, if a corresponding frequency line of the first patch is missing, wherein the combiner is configured to combine the first patch, the modified second patch and the first band of the input signal.

8. The apparatus according to claim 1 , comprising a power controller configured to control the scaling of the input signal according to the first and the second patching algorithm or configured to control the scaling of the first patch and the second patch, wherein the power controller controls the scaling based on spectral envelope data comprised by the input signal and based on at least one stored patch scaling control parameter or patch scaling control data comprised by the input signal.

9. The apparatus according to claim 8 , comprising a first power adjuster configured to scale the input signal according to the first patching algorithm or to scale the first patch, and comprising a second power adjuster configured to scale the input signal according to the second patching algorithm or to scale the second patch, wherein the power controller is configured to control the first power adjuster and the second power adjuster.

10. The apparatus according to claim 8 , comprising a noise adder and a missing harmonic adder, wherein the noise adder is configured to generate a noise patch based on a noise data comprised by the input signal, wherein the missing harmonic adder is configured to generate a missing harmonic patch based on a missing harmonic data comprised by the input signal, wherein the power controller is configured to control a scaling of the noise patch and the missing harmonic patch based on the spectral envelope data, and wherein the combiner is configured to combine the first patch, the second patch, the first band of the input signal, the noise patch and the missing harmonic patch to acquire the bandwidth extended signal, wherein the power controller controls the scaling of the first patch, the second patch, the noise patch and the missing harmonic patch based on the spectral envelope data, so that the spectral envelope criterion is fulfilled.

11. An apparatus for providing a bandwidth reduced signal based on an input signal, comprising:
a spectral envelope data determiner configured to determine spectral envelope data based on a high-frequency band of the input signal; a patch scaling control data generator configured to generate patch scaling control data for scaling the bandwidth reduced signal at a decoder or for scaling a first patch and a second patch by the decoder, so that a bandwidth extended signal generated by the decoder fulfills a spectral envelope criterion, wherein the spectral envelope criterion is based on the spectral envelope data wherein the first patch is generated from a first band of the bandwidth reduced signal according to a first patching algorithm and the second patch is generated from the first band of the bandwidth reduced signal according to a second patching algorithm, wherein a spectral density of the second patch generated according to the second patching algorithm is higher than a spectral density of the first patch generated according to the first patching algorithm; an output interface configured to combine a low frequency band of the input signal, the spectral envelope data and the patch scaling control data to acquire the bandwidth reduced signal and configured to provide the bandwidth reduced signal for transmission or storage.

12. The apparatus according to claim 11 , wherein the patch scaling control data generator comprises:
the patch generator configured to generate a first patch from the low frequency band of the input signal according to a first patching algorithm and configured to generate a second patch from the low frequency band of the input signal according to a second patching algorithm, wherein a spectral density of the second patch generated according to the second patching algorithm is higher than the spectral density of the first patch generated according to the first patching algorithms; and a comparator configured to compare the first patch, the second patch and the high frequency band of the input signal to acquire the patch scaling control data.

13. The apparatus according to claim 11 , comprising a patch scaling control parameter memory configured to store and provide a plurality of patch scaling control parameters, wherein the patch scaling control data generator is configured to analyze the input signal and configured to generate the patch scaling control data based on stored patch scaling control parameters se

Assignees

• Fraunhofer Ges Forschung

Inventors

• Nagel Frederik
• Disch Sascha
• Neuendorf Max
• Bayer Stefan
• Gayer Marc
• Lohwasser Markus
• Rettelbach Nikolaus
• Kraemer Ulrich

Classifications

• G10L21/038 Primary

  using band spreading techniques · CPC title