Voice interference correction for mixed voice and spread spectrum data signaling

• US 20060282184A1
• Filed: 06/08/2005
• Published: 12/14/2006
• Est. Priority Date: 06/08/2005
• Status: Active Grant

• Current Assignee: Polycom Incorporated (Plantronics, Inc.)
• Original Assignee: Polycom Incorporated (Plantronics, Inc.)
• Inventors: Elias, Eric
• Granted Patent: US 8,126,029 B2
• Time in Patent Office: Days
• US Class Current: 700/94
• CPC Class Codes: H04M 11/06 Simultaneous speech and data transmission, e.g. telegraphic transmission over the same conductors
• CPC Class Codes: H04M 11/066 Telephone sets adapted for data transmision

Abstract

A method, a process and an audio system for embedding bit stream in a voice signal is disclosed. A voice/data interference signal is composed and supplied to the mixer of the voice signal and the data signal such that the resulting mixed signal effectively cancels the interference and allows the interference-free signal being transmitted to the audio signal receiver/decoder. The decoder may decode the data without interference errors. A method using profile shaping to mask the noise due to modulated carrier signal is also disclosed.

Claims

1. A method for reducing bit stream errors in an audio system, wherein a bit stream modulates a chip sequence and an audio carrier signal to form a modulated signal, wherein the modulated signal is embedded in an audio signal, the method comprising:

calculating an interference among the audio signal, the chip sequence and the audio carrier signal; and

summing the audio signal and the modulated signal and subtracting the interference.

2. A method for embedding a bit stream in an audio stream in an audio system, the method comprising:

forming a modulated signal to represent the bit stream by modulating a combination of an audio carrier signal and a chip sequence;

calculating an interference between the audio stream and the combination of the audio carrier signal and the chip sequence; and

summing the audio stream and the modulated signal, and subtracting the interference to form a mixed signal.

3. The method of claim 2,

wherein modulating an audio carrier signal to represent the bit stream, the modulation method is a phase shifting keying method.

4. The method of claim 2,

wherein modulating an audio carrier signal to represent the bit stream includes direct spread spectrum.

5. The method of claim 2, further comprising:

obtaining the spectra profile of the audio stream; and

shaping the audio carrier signal according to the audio stream profile before the audio carrier signal is used to modulate the bit stream.

6. The method of claim 5, further comprising:

unshaping the mixed signal to normal profile before demodulating the mixed signal; and

demodulating the mixed signal to retrieve the bit stream.

7. The method of claim 2, further comprising:

demodulating the mixed signal to retrieve the bit stream.

8. A signal processor for an audio system, the processor comprising:

a processing module operable for,

modulating a chip sequence and an audio carrier signal to form a modulated signal to represent a bit stream, wherein the modulated signal is embedded in an audio signal;

calculating an interference among the audio stream, the chip sequence and the modulated audio carrier signal; and

summing the audio stream and the modulated audio carrier signal, and subtracting the interference to form a mixed signal.

9. The signal processor of claim 8,.

wherein modulating an audio carrier signal to represent the bit stream, the modulation method is a phase shifting keying method.

10. The signal processor of claim 8,

wherein modulating an audio carrier signal to represent the bit stream includes direct spread spectrum.

11. The signal processor of claim 8, wherein the processing module is further operable for:

obtaining the spectra profile of the audio stream; and

shaping the audio carrier signal according to the audio stream profile before the audio carrier signal is used to modulate the bit stream.

12. The signal processor of claim 11, wherein the processing module is further operable for:

unshaping the mixed signal to normal profile before demodulating the mixed signal; and

demodulating the mixed signal to retrieve the bit stream.

13. The signal processor of claim 8, wherein the processing module is further operable for:

demodulating the mixed signal to retrieve the bit stream.

14. An audio system, comprising:

a microphone; and

a processor module coupled to the microphone, wherein the processing module is operable for;

receiving a bit stream;

modulating a chip sequence and an audio carrier signal to form a modulated signal to represent the bit stream, wherein the modulated signal is embedded in an audio signal;

calculating an interference between the audio stream and the modulated audio carrier signal; and

summing the audio stream and the modulated audio carrier signal, and subtracting the interference to form a mixed signal.

15. The audio system of claim 14,

wherein modulating an audio carrier signal to represent the bit stream, the modulation method is a phase shifting keying method.

16. The audio system of claim 14,

wherein modulating an audio carrier signal to represent the bit stream includes direct spread spectrum.

17. The audio system of claim 14, wherein the processing module is operable for:

obtaining the spectra profile of the audio stream; and

shaping the audio carrier signal according to the audio stream profile before the audio carrier signal is used to modulate the bit stream.

18. The audio system of claim 17, wherein the processing module is operable for:

unshaping the mixed signal to normal profile before demodulating the mixed signal; and

demodulating the mixed signal to retrieve the bit stream.

19. The audio system of claim 14, wherein the processing module is operable for:

demodulating the mixed signal to retrieve the bit stream.

20. The audio system of 14, further comprising:

a network interface coupled the process module.

21. The audio system of 20,

wherein the network interface is operable to connect to a Plane Old Telephone Service (POTS) network.

22. The audio system of 20,

wherein the network interface is operable to connect to a radio that broadcasts the mix signal.

23. The audio system of 20,

wherein the network interface is operable to record the mixed signal in a medium.