SIGNAL PROCESSOR

• US 20180315439A1
• Filed: 03/26/2018
• Published: 11/01/2018
• Est. Priority Date: 04/28/2017
• Status: Active Grant

• Current Assignee: NXP B.V. (NXP Semiconductors NV)
• Original Assignee: NXP B.V. (NXP Semiconductors NV)
• Inventors: Madhu, Nilesh, Tirry, Wouter Joos
• Granted Patent: US 10,453,469 B2
• Time in Patent Office: Days
• CPC Class Codes: G10L 19/093 using sinusoidal excitation models
• CPC Class Codes: G10L 21/0216 characterised by the method used for estimating noise
• CPC Class Codes: G10L 21/0232 Processing in the frequency domain
• CPC Class Codes: G10L 21/0364 for improving intelligibility
• CPC Class Codes: G10L 21/038 using band spreading techniques
• CPC Class Codes: G10L 25/18 the extracted parameters being spectral information of each sub-band
• CPC Class Codes: G10L 25/21 the extracted parameters being power information
• CPC Class Codes: G10L 25/90 Pitch determination of speech signals

Abstract

A signal processor comprising: a modelling block, configured to receive a frequency-domain-input-signal, a fundamental-frequency-signal representative of a fundamental frequency of the frequency-domain-input-signal; and configured to provide a pitch-model-signal based on a periodic function, the pitch-model-signal spanning a plurality of discrete frequency bins, each discrete frequency bin having a respective discrete frequency bin index, wherein within each discrete frequency bin the pitch-model-signal is defined by: the periodic function; the fundamental frequency; the frequency-domain-input-signal; and the respective discrete frequency bin index. The signal processor further comprises a manipulation block, configured to provide an output-signal based on the frequency-domain-input-signal and the pitch-model-signal.

Claims

1. A signal processor comprising:

a modelling block, comprising

a modelling-block-input-signal-terminal configured to receive a frequency-domain-input-signal;

a fundamental-frequency-input-terminal configured to receive a fundamental-frequency-signal representative of a fundamental frequency of the frequency-domain-input-signal; and

a modelling-output-terminal, configured to provide a pitch-model-signal based on a periodic function, the pitch-model-signal spanning a plurality of discrete frequency bins, each discrete frequency bin having a respective discrete frequency bin index, wherein within each discrete frequency bin the pitch-model-signal is defined by;

the periodic function;

the fundamental frequency;

the frequency-domain-input-signal; and

the respective discrete frequency bin index,

a manipulation block, comprising;

a manipulation-block-input-signal-terminal configured to receive a representation of the frequency-domain-input-signal;

a model-input-terminal configured to receive a representation of the pitch-model-signal from the modelling block; and

an output-terminal,

wherein the manipulation block is configured to provide an output-signal, to the output-terminal, based on the frequency-domain-input-signal and the pitch-model-signal.

2. The signal processor of claim 1, wherein the pitch-model-signal comprises an amplitude for each discrete frequency bin, each respective amplitude determined in accordance with the frequency-domain-input-signal.

3. The signal processor of claim 1, wherein the pitch-model-signal comprises an offset, added to the periodic function, for each discrete frequency bin, each respective offset determined in accordance with the frequency-domain-input-signal.

4. The signal processor of claim 1, wherein the pitch-model-signal is limited to an upper maximum value for each discrete frequency bin, each respective upper maximum value determined in accordance with the frequency-domain-input-signal.

5. The signal processor of claim 1, wherein the pitch-model-signal is limited to a lower minimum value for each discrete frequency bin, each respective lower minimum value determined in accordance with the frequency-domain-input-signal.

6. The signal processor of claim 1, wherein the pitch-model-signal is based on the modulus of the periodic function exponentiated to a power for each discrete frequency bin, each respective power determined in accordance with the frequency-domain-input-signal.

7. The signal processor of claim 1, wherein the pitch-model-signal comprises a frequency-offset determined in accordance with the frequency-domain-input-signal.

8. The signal processor of claim 1, wherein the pitch-model-signal comprises a frequency-offset for each discrete frequency bin, each respective frequency-offset determined in accordance with the frequency-domain-input-signal.

9. The signal processor of claim 1, wherein the periodic function is a cosine function.

10. The signal processor of claim 1, further comprising an a-priori-signal-to-noise-ratio-estimation block, comprising:

a noise-power-estimate-terminal, configured to receive a noise-power-estimate-signal based on the frequency-domain-input-signal;

a manipulation-input-terminal coupled to the output-terminal of the manipulation block and configured to receive the output-signal; and

an a-priori-signal-to-noise-ratio-estimation-output terminal, configured to provide an a-priori-signal-to-noise-ratio-estimation-signal based on the noise-power-estimate-signal and the output-signal.

11. The signal processor of claim 1, wherein the manipulation block further comprises an envelope-estimation-block configured to receive the frequency-domain-input-signal and determine an envelope-signal based on the frequency-domain-input-signal and predetermined-envelope-data, and

wherein the manipulation block is configured to provide the output-signal based on a combination of the pitch-model-signal and the envelope-signal.

12. The signal processor of claim 11, wherein the manipulation block is configured to provide the output-signal based on a product of the envelope-signal with the pitch-model-signal for a selected subset of the plurality of discrete frequency bins.

13. The signal processor of claim 12, wherein the selected subset of the plurality of discrete frequency bins relate to frequencies that exceed a bandwidth of the frequency-domain-input-signal.

14. A computer program, which when run on a computer, causes the computer to configure a signal processor of claim 1.

15. A method of signal processing comprising:

receiving a frequency-domain-input-signal;

receiving a fundamental-frequency-signal representative of a fundamental frequency of the frequency-domain-input-signal; and

providing a pitch-model-signal based on a periodic function, the pitch-model-signal spanning a plurality of discrete frequency bins, each discrete frequency bin having a respective discrete frequency bin index, wherein within each discrete frequency bin the pitch-model-signal is defined by;

the periodic function;

the fundamental frequency;

the frequency-domain-input-signal; and

the respective discrete frequency bin index,

receiving a representation of the frequency-domain-input-signal;

receiving a representation of the pitch-model-signal; and

providing an output-signal based on the frequency-domain-input-signal and the pitch-model-signal.