AUDIO SIGNAL SYNTHESIS

• US 20100131276A1
• Filed: 07/06/2006
• Published: 05/27/2010
• Est. Priority Date: 07/14/2005
• Status: Abandoned Application

• Current Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Original Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Inventors: Sluijter, Robert Johannes, Den Brinker, Albertus Cornelis
• Application Number:
  US11/995,345
• Publication Number:
  US 20100131276A1
• Time in Patent Office: Days
• US Class Current: 704/262
• CPC Class Codes: G10L 13/033 Voice editing, e.g. manipulating the voice of the synthesiser
• CPC Class Codes: G10L 19/093 using sinusoidal excitation models
• CPC Class Codes: G10L 2021/0135 Voice conversion or morphing

Abstract

A device (2) for changing the pitch of an audio signal (r), such as a speech signal, comprises a sinusoidal analysis unit (21) for determining sinusoidal parameters of the audio signal (r), a parameter production unit (22) for predicting the phase of a sinusoidal component, and a sinusoidal synthesis unit (23) for synthesizing the parameters to produce a reconstructed signal (r′). The parameter production unit (22) receives, for each time segment of the audio signal, the phase of the previous time segment to predict the phase of the current time segment.

Claims

1. A signal synthesis device (20) for synthesizing an audio signal (r′

), the device comprising;

a sinusoidal synthesis unit (23) for synthesizing the audio signal (r′

) using at least one frequency parameter (f′

) representing a frequency of the audio signal and at least one phase parameter (φ

′

) representing a phase of the audio signal, and

a parameter production unit (22) for producing the phase parameter (φ

′

) using the frequency parameter (f) and the audio signal (r′

).

2. The device according to claim 1, wherein the synthesized audio signal (r′

) comprises time segments, and wherein the parameter production unit (22) is arranged for producing the current phase parameter (φ

′

) using a previous time segment of the audio signal (r′

).

3. The device according to claim 1, wherein the parameter production unit (22) comprises a phase determination unit (21′

) arranged for determining a set of phase/frequency pairs, each phase/frequency pair representing the phase of a frequency of the audio signal (r′

).

4. The device according to claim 3, wherein the parameter production unit (22) further comprises a phase prediction unit (28) arranged for:

comparing the frequency parameter (f, f′

) with the set of phase/frequency pairs and selecting the phase/frequency pair nearest to the frequency parameter (f′

), and

producing the phase parameter (φ

′

) using the frequency parameter (f′

) and the selected phase.

5. The device according to claim 1, wherein the parameter production unit (22) comprises a frequency modification unit (27) for modifying the frequency parameter (f) in response to a control parameter (C).

6. The device according to claim 1, wherein the sinusoidal synthesis unit (23) additionally uses an amplitude parameter (A).

7. The device according to claim 1, further comprising a gain control unit (24) for multiplying the synthesized audio signal (r′

) by a gain parameter (G).

8. The device according to claim 1, further comprising a sinusoidal analysis unit (21) for receiving an input audio signal (r) and producing a frequency parameter (f′

) and a phase parameter (φ

′

).

9. The device according to claim 8, further comprising:

a further sinusoidal synthesis unit (23′

) for producing a synthesized audio signal, and

a comparison unit (26) for comparing the synthesized audio signal and the input audio signal so as to produce a gain parameter (G).

10. The device according to claim 2, further comprising a segmentation unit (25) for dividing the audio signal (r) into time segments.

11. The device according to claim 2, further comprising an overlap-and-add unit (25′

) for joining the time segments of the synthesized audio signal (r′

).

12. The device according to claims 10 and 11, wherein the segmentation unit (25) is controlled by a first overlap parameter (updin) and wherein the overlap-and-add unit (25′

) is controlled by a second overlap parameter (updout), and wherein the device is arranged for time scaling by varying the overlap parameters (updin, updout).

13. A speech conversion device (1), comprising:

a linear prediction analysis unit (10) for producing prediction parameters (p) and a residual signal (r) in response to an input speech signal (x),

a pitch adaptation unit (20) for adapting the pitch of the residual signal (r) so as to produce a pitch adapted residual signal (r′

), and

a linear prediction synthesis unit (30) for synthesizing an output speech signal (y) in response to the pitch adapted residual signal (r′

),

wherein the pitch adaptation unit (20) comprises a device according to claim 5.

14. The speech conversion device according to claim 13, further comprising a modification unit (40) for modifying the prediction parameters.

15. An audio system, comprising a device according to claim 1.

16. An audio signal decoder (5), comprising:

a sinusoidal synthesis unit (23) for synthesizing the audio signal (r′

) using at least one frequency parameter (f′

) representing a frequency of the audio signal and at least one phase parameter (φ

′

) representing a phase of the audio signal, and

a parameter production unit (22) for producing the phase parameter (φ

′

) using the frequency parameter (f) and the audio signal (r′

).

17. A method of synthesizing an audio signal (r′

), the method comprising the steps of;

synthesizing the audio signal (r′

) using at least one frequency parameter (f, f′

) representing a frequency of the audio signal and at least one phase parameter (φ

′

) representing a phase of the audio signal, and

producing the phase parameter (φ

′

) using the frequency parameter (f, f′

) and the audio signal (r′

).

18. The method according to claim 17, wherein the synthesized audio signal (r′

) comprises time segments, and wherein the parameter production unit (22) is arranged for producing the current phase parameter (φ

′

) using a previous time segment of the audio signal (r′

).

19. The method according to claim 17, wherein the phase prediction step comprises the sub-steps of determining a set of phase/frequency pairs, each phase/frequency pair representing the phase of a frequency of the audio signal (r′

).

20. The method according to claim 17, wherein the phase prediction step further comprises the sub-steps of

comparing the frequency parameter (f′

) with the set of phase/frequency pairs and selecting the phase/frequency pair nearest to the frequency parameter (f′

), and

producing the phase parameter (φ

′

) using the frequency parameter (f′

) and the selected phase.

21. The method according to claim 17, wherein the phase prediction step comprises the sub-step of modifying the frequency parameter (f′

) in response to a control parameter (C).

22. A speech conversion method, comprising the steps of:

producing prediction parameters (p) and a residual signal (r) in response to an input speech signal (x),

adapting the pitch of the residual signal (r) so as to produce a pitch adapted residual signal (r′

), and

synthesizing an output speech signal (y) in response to the pitch adapted residual signal (r′

),

wherein the pitch adaptation step comprises a sub-step of changing the frequency of an audio signal according to claim 21.

23. A method according to claim 17 or 22, further comprising the step of time scaling.

24. A computer program product for carrying out the method according to claim 17 or 22.