Selective shaping of communication signals

• US 8,275,147 B2
• Filed: 05/05/2005
• Issued: 09/25/2012
• Est. Priority Date: 05/05/2004
• Status: Active Grant

• Current Assignee: Deka Products Limited Partnership
• Original Assignee: Deka Products Limited Partnership
• Inventors: Beavis, Russell H., Kane, Derek G.
• Primary Examiner(s): FAULK, DEVONA E
• Application Number:
  US11/122,446
• Publication Number:
  US 20050249361A1
• Time in Patent Office: 2,700 Days
• Field of Search: 381/92, 381/60, 381/66, 381/93, 381 941- 943, 381/94.7, 381/26, 381/314, 704/228, 704/233, 455/570
• US Class Current: 381/92
• CPC Class Codes: G01S 3/8006 Multi-channel systems specially adapted for direction-finding, i.e. having a single aerial system capable of giving simultaneous indications of the directions of different signals
• CPC Class Codes: G01S 3/8083 determining direction of source
• CPC Class Codes: G10K 11/346 using phase variation
• CPC Class Codes: G10L 2021/02165 Two microphones, one receiving mainly the noise signal and the other one mainly the speech signal
• CPC Class Codes: G10L 21/0208 Noise filtering
• CPC Class Codes: H04R 2201/401 2D or 3D arrays of transducers
• CPC Class Codes: H04R 2201/403 Linear arrays of transducers
• CPC Class Codes: H04R 2410/01 Noise reduction using microphones having different directional characteristics
• CPC Class Codes: H04R 25/407 Circuits for combining signals of a plurality of transducers
• CPC Class Codes: H04R 27/00 Public address systems circuits for preventing acoustic reaction H04R3/02; circuits for distributing signals to loudspeakers H04R3/12; monitoring or testing arrangements for public address systems H04R29/007; amplifiers H03F
• CPC Class Codes: H04R 3/005 for combining the signals of two or more microphones specially adapted for hearing aids H04R25/407

Abstract

Angular discrimination between signals is described. Multiple signals are sampled with multiple signal sensors spatially separated from each other. Respective transform signals are determined that are representative of each sampled signal. If a difference between the transform signals in a given transform kernel bin is greater than a difference threshold, a first transform signal is modified by altering that kernel bin. Then the resulting modified transform signal is inverse transformed.

Claims

1. A method of angular discrimination between signals, the method comprising:

sampling a plurality of signals with at least three non-coliinear microphones spatially separated from each other;

determining respective transform signals representative of each sampled signal;

if a phase difference between the transform signals within a transform kernel bin is greater than a phase difference threshold, modifying a first transform signal by altering the kernel bin; and

inverse transforming the modified transform signal.

2. A method according to claim 1, further comprising outputting the inverse transformed signal to a user.

3. A method according to claim 1, wherein modifying a first transform signal by altering the kernel bin further comprising reducing the transform kernel bin using a comb filter funtion.

4. A method according to claim 1, wherein modifying a first transform signal by altering the kernel bin further comprising reducing the transform kernel bin to zero.

5. A method according to claim 1, wherein the transform signals are Fourier transforms of the signals.

6. A method according to claim 1, wherein there are two signals.

7. A method according to claim 1, wherein there are two signal sensors.

8. A method according to claim 1, wherein the signals are audio signals.

9. A method according to claim 1, wherein the signals are radio signals.

10. An audio system adapted to use the method according to any of claims 1-9.

11. An audio system according to claim 10, wherein the system is part of an assisted listening device.

12. An audio system according to claim 10, wherein the system is part of a wireless telephone, a speaker phone, a speaker podium, or a boom microphone.

13. A method of angular discrimination between signals, the method comprising:

sampling a plurality of sound signals with at least three non-collinear microphones spatially separated from each other;

determining respective transform signals representative of each sampled signal by performing a Fourier transform of each sampled signal;

if a phase difference between the transform signals within a transform kernel bin is greater than a phase difference threshold, modifying a first transform signal by reducing the transform kernel bin to zero; and

inverse transforming the modified transform signal.

14. A method according to claim 13, wherein the inverse transformed signal is output to a user.

15. A method according to claim 13, wherein modifying a first transform signal by altering the kernel bin further comprising reducing the transform kernel bin a comb filter function.

16. A method according to claim 13, wherein the signals are audio signals.

17. A method according to claim 13, wherein the signals are radio signals.