Tone clamping and replacement

• US 7,313,233 B2
• Filed: 06/10/2003
• Issued: 12/25/2007
• Est. Priority Date: 06/10/2003
• Status: Expired due to Fees

• Current Assignee: Intel Corporation
• Original Assignee: Intel Corporation
• Inventors: Rhemtulla, Amin F., Chen, Ling, Lam, Siu H.
• Primary Examiner(s): Tsang, Fan
• Assistant Examiner(s): Anwah, Olisa
• Application Number:
  US10/459,309
• Publication Number:
  US 20040252813A1
• Time in Patent Office: 1,659 Days
• Field of Search: 379/88.08, 379/386, 379/351, 379/286, 379/283, 379/88.07, 379/88.09, 379/88.16, 379/202.01, 370/526, 370/525, 370/260, 370268-269, 370286-292
• US Class Current: 379/406.01
• CPC Class Codes: H04M 3/56 Arrangements for connecting several subscribers to a common circuit, i.e. affording conference facilities video conference systems H04N7/15
• CPC Class Codes: H04M 7/006 Networks other than PSTN/ISDN providing telephone service, e.g. Voice over Internet Protocol (VoIP) , including next generation networks with a packet-switched transport layer H04L65/00 takes precedence; aspects not specific to the type of network H04M3/00; special services in those networks H04M3/42
• CPC Class Codes: H04M 7/1295 Details of dual tone multiple frequency signalling
• CPC Class Codes: H04Q 1/45 using multi-frequency signalling H04Q1/46 takes precedence

Abstract

A method and apparatus to manage tone clamping are described.

Claims

1. A method to manage tone clamping, comprising:

receiving a stream of audio information;

detecting tone information in said stream;

replacing said tone information with background noise in response to detecting a tone in said tone information, wherein said background noise corresponds to background noise measured for said stream of audio; and

wherein said replacing comprises;

removing said tone information from said stream;

generating said background noise; and

inserting said background noise into said stream where said tone information was removed;

wherein said generating said background noise comprises extracting at least one background noise parameter from said stream and synthesizing said background noise using said extracted background noise parameter.

2. The method of claim 1, wherein said tone information represents a Dual Tone Multi-Frequency (DTMF) tone.

3. The method of claim 1, wherein said detecting comprises:

extracting at least one tone parameter from said stream;

comparing said extracted tone parameter with a reference tone parameter; and

creating an output signal indicating whether said tone information is present in said stream in accordance with said comparison.

4. The method of claim 1, wherein said extracting comprises:

selecting a time period for said stream; and

extracting said background noise parameter using said time period.

5. The method of claim 4, wherein said background noise parameter is at least one of a parameter representing full band energy, low band energy, zero-crossing rate, and a spectral measure.

6. A system, comprising:

a first call terminal to originate audio information;

a gateway connected to said first call terminal to receive said audio information;

a tone clamping module connected to said gateway, said tone clamping module clamping tone information in said audio information by replacing said tone information with background noise in response to detecting a tone in said tone information, wherein said background noise corresponds to background noise measured for said stream of audio;

a second call terminal to receive said tone clamped audio information; and

wherein said tone clamping module further comprises a background noise generator to synthesize and insert background noise into said audio information to replace said tone information;

wherein said background noise generator extracts at least one background noise parameter from said audio information, and uses said background noise parameter to synthesize said background noise.

7. The system of claim 6, wherein said tone clamping module further comprises:

a buffer to store said audio information;

a tone detector to detect tone information in said audio information; and

a tone damper to remove tone information from said audio information.

8. The system of claim 7, further comprising a tone replacement manager to send control information to said buffer, tone detector, tone damper and background noise generator.

9. An apparatus, comprising:

a buffer to store audio information;

a tone detector to detect tone information in said audio information;

a tone damper to remove tone information from said audio information; and

a background noise generator to synthesize and insert background noise into said audio information to replace said tone information in response to detecting a tone in said tone information, wherein said background noise corresponds to background noise measured for said stream of audio; and

wherein said background noise generator extracts at least one background noise parameter from said audio information, and uses said background noise parameter to synthesize said background noise.

10. The apparatus of claim 9, further comprising a tone replacement manager to send control information to said buffer, tone detector, tone damper and background noise generator.

11. The apparatus of claim 9, wherein said tone detector may detect said tone information using at least one tone parameter, and send an output signal indicating if said tone information is detected.

12. The method of claim 9, wherein said background noise parameter is at least one of a parameter representing full band energy, low band energy, zero-crossing rate, and a spectral measure.

13. An article comprising:

a storage medium;

said storage medium including stored instructions that, when executed by a processor, result in managing by receiving a stream of audio information, detecting tone information in said stream, and replacing said tone information with background noise in response to detecting a tone in said tone information, wherein said background noise corresponds to background noise measured for said stream of audio; and

wherein said replacing comprises removing said tone information from said stream, generating said background noise, and inserting said background noise into said stream where said tone information was removed;

wherein said generating said background noise comprises extracting at least one background noise parameter from said stream, and synthesizing said background noise using said extracted background noise parameter.

14. The article of claim 13, wherein the stored instructions, when executed by a processor, further result in said detecting by extracting at least one tone parameters from said stream, comparing said extracted tone parameter with a reference tone parameter;

and creating an output signal indicating whether said tone information is present in said stream in accordance with said comparison.

15. The article of claim 13, wherein the stored instructions, when executed by a processor, further result in said extracting comprises selecting a time period for said stream, and extracting said background noise parameter using said time period.