Filtering audio signals from a combined microphone/speaker earpiece

• US 5,949,891 A
• Filed: 11/16/1994
• Issued: 09/07/1999
• Est. Priority Date: 11/24/1993
• Status: Expired due to Term

• Current Assignee: Intel Corporation
• Original Assignee: Intel Corporation
• Inventors: Wagner, Larry, Wu, Carol
• Primary Examiner(s): Chang, Vivian
• Assistant Examiner(s): NGUYEN, DUC MINH
• Application Number:
  US08/342,270
• Time in Patent Office: 1,756 Days
• Field of Search: 381/68-68.6, 381/71, 381/95, 381/94, 381/71.8, 381/66, 381/98, 381/103, 381/26, 381/151, 379/390, 379/399, 379/406-407, 379/410-411
• US Class Current: 381/98
• CPC Class Codes: G06T 1/00 General purpose image data processing
• CPC Class Codes: G06T 2200/16 involving adaptation to the client's capabilities
• CPC Class Codes: H04L 12/1813 for computer conferences, e.g. chat rooms instant messaging H04L51/04; protocols for multimedia communication H04L65/1101; arrangements for multi-party communication H04L65/403; telephonic conference arrangements H04M3/56; television conference systems H04N7/15
• CPC Class Codes: H04L 12/1822 Conducting the conference, e.g. admission, detection, selection or grouping of participants, correlating users to one or more conference sessions, prioritising transmission
• CPC Class Codes: H04M 3/567 Multimedia conference systems
• 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 9/08 Two-way loud-speaking telephone systems with means for conditioning the signal, e.g. for suppressing echoes for one or both directions of traffic
• CPC Class Codes: H04N 21/4143 embedded in a Personal Computer [PC]
• CPC Class Codes: H04N 21/643 Communication protocols network streaming protocols, e.g. real-time transport protocol [RTP] or real-time control protocol [RTCP], H04L65/65
• CPC Class Codes: H04N 7/148 Interfacing a video terminal to a particular transmission medium, e.g. ISDN
• CPC Class Codes: H04N 7/15 Conference systems
• CPC Class Codes: H04Q 2213/13003 Constructional details of switching devices
• CPC Class Codes: H04Q 2213/13103 Memory
• CPC Class Codes: H04Q 2213/13106 Microprocessor, CPU
• CPC Class Codes: H04Q 2213/13204 Protocols
• CPC Class Codes: H04Q 2213/13209 ISDN
• CPC Class Codes: H04Q 2213/1324 Conference call
• CPC Class Codes: H04Q 2213/13299 Bus
• CPC Class Codes: H04Q 2213/13337 Picturephone, videotelephony
• CPC Class Codes: H04Q 2213/13389 LAN, internet

Abstract

An audio processing system applies a filter to convert the audio signals generated by the microphone of a combined microphone/speaker earpiece into filtered audio signals, where the filter is designed to correct for distortions in the audio signals that result from the microphone being part of the combined earpiece.

Claims

1. A process for processing audio signals, comprising the steps of:

(a) generating audio signals corresponding to sounds emanating from a local user using a microphone that is part of a combined microphone/speaker earpiece;

(b) filtering the audio signals using a local audio processing system including a digital filter which is implemented as a stackable driver on a computer processor to reduce distortions in the audio signals, wherein the filter is implemented using a cascade of a second-order high-pass Chebyshev Type I Infinite Impulse Response filter and a sixth-order Infinite Impulse Response filter designed using Steiglitz approximation; and

(c) transmitting the filtered audio signals from the local audio processing system to a remote audio processing system for playback to a remote user.

2. The process of claim 1, wherein the stackable driver is implemented under a Spectron Microsystems SPOX™

operating system.

3. The process of claim 1, wherein the stackable driver is selectively enabled and disabled.

4. The process of claim 1, wherein the filter is designed to correct for distortions due to reverberation signals that reflect off the cheek of a user of the earpiece.

5. The process of claim 1, wherein the filter is designed to correct for distortions due to sounds that become out of phase at the microphone.

6. The process of claim 1, wherein the filter is designed to correct for distortions due to directionality/loss of relatively high frequencies of the audio signals.

7. The process of claim 1, wherein the filter produces an approximately 3 dB bump at approximately 2 kHz.

8. The process of claim 1, wherein the combined earpiece is a Plantronics Enterprise™

headset.

9. The process of claim 1, wherein step (b) comprises the steps of:

(1) digitizing the audio signals using the local audio processing system; and

(2) applying the digital filter to the digital audio signals using the local audio processing system to generate the filtered audio signals, and step (c) comprises the steps of;

(1) compressing the filtered audio signals using the local audio processing system; and

(2) transmitting the compressed audio signals from the local audio processing system to the remote audio processing system for decompression and playback to the remote user; and

further comprising the steps of;

(d) receiving remote compressed audio signals by the local audio processing system from the remote audio processing system;

(e) decompressing the remote compressed audio signals by the local audio processing system; and

(f) playing the remote decompressed audio signals with a speaker that is part of the combined microphone/speaker earpiece.

10. The process of claim 1, wherein:

the combined earpiece is a Plantronics Enterprise™

headset;

the digital filter is implemented as a stackable driver on a computer processor under a Spectron Microsystems SPOX™

operating system;

the stackable driver is selectively enabled and disabled; and

the digital filter is implemented using a cascade of a second-order high-pass Chebyshev Type I Infinite Impulse Response filter and a sixth-order Infinite Impulse Response filter designed using Steiglitz approximation that produces an approximately 3 dB bump at approximately 2 kHz.

11. The process of claim 10, wherein the digital filter is designed to correct for distortions due to reverberation signals that reflect off the cheek of a user of the earpiece, sounds from the user'"'"'s mouth that become out of phase at the microphone, and directionality/loss of relatively high frequencies of the audio signals.

12. The process of claim 10, wherein step (c) comprises the steps of:

(1) compressing the filtered audio signals using the local audio processing system; and

(2) transmitting the compressed audio signals from the local audio processing system to the remote audio processing system for decompression and playback to the remote user.

13. A system for processing audio signals, comprising:

(a) an earpiece comprising a microphone; and

(b) a local audio processing system, wherein;

the microphone is adapted to generate audio signals corresponding to sounds emanating from a local user;

the local audio processing system is adapted to apply a digital filter implemented as a stackable driver on a computer processor to the audio signals to reduce distortions in the audio signals, wherein the filter is implemented using a cascade of a second-order high-pass Chebyshev Type I Infinite Impulse Response filter and a sixth-order Infinite Impulse Response filter designed using Steiglitz approximation; and

the local audio processing system is adapted to transmit the filtered audio signals from the local audio processing system to a remote audio processing system for playback to a remote user.

14. The system of claim 13, wherein the stackable driver is implemented under a Spectron Microsystems SPOX™

operating system.

15. The system of claim 13, wherein the stackable driver is selectively enabled and disabled.

17. The system of claim 13, wherein the filter is designed to correct for distortions due to sounds that become out of phase at the microphone.

18. The system of claim 13, wherein the filter is designed to correct for distortions due to directionality/loss of relatively high frequencies of the audio signals.

19. The system of claim 13, wherein the filter is adapted to produce an approximately 3 dB bump at approximately 2 kHz.

20. The system of claim 13, wherein the combined earpiece is a Plantronics Enterprise™

headset.

21. The system of claim 13, wherein:

the local audio processing system is adapted to digitize the audio signals;

the local audio processing system is adapted to apply the digital filter to the digital audio signals;

the local audio processing system is adapted to compress the filtered audio signals;

the local audio processing system is adapted to transmit the compressed audio signals to the remote audio processing system for decompression and playback to the remote user;

the local audio processing system is adapted to receive remote compressed audio signals from the remote audio processing system;

the local audio processing system is adapted to decompress the remote compressed audio signals; and

a speaker of the earpiece is adapted to render the remote decompressed audio signals.

22. The system of claim 13, wherein:

the combined carpiece is a Plantronics Enterprise™

headset;

the digital filter is implemented as a stackable driver on a computer processor under a Spectron Microsystems SPOX™

operating system;

the stackable driver is selectively enabled and disabled; and

the digital filter is implemented using a cascade of a second-order high-pass Chebyshev Type I Infinite Impulse Response filter and a sixth-order Infinite Impulse Response filter designed using Steiglitz approximation that produces an approximately 3 dB bump at approximately 2 kHz.

23. The system of claim 22, wherein the digital filter is designed to correct for distortions due to reverberation signals that reflect off the cheek of a user of the earpiece, sounds from the user'"'"'s mouth that become out of phase at the microphone, and directionality/loss of relatively high frequencies of the audio signals.

24. The system of claim 22, wherein:

the local audio processing system is adapted to compress the filtered audio signals; and

the local audio processing system is adapted to transmit the compressed audio signals to the remote audio processing system for decompression and playback to the remote user.

16. The system of clain 13, wherein the filter is designed to correct for distortions due to reverberation signals that reflect off the cheek of a user of the earpiece.

25. A process for processing audio signals, comprising the steps of:

(a) generating, with a microphone of an earpiece comprising the microphone, audio signals corresponding to sounds emanating from a local user having a head having a mouth, an ear, and a cheek between the mouth and ear;

(b) filtering, with a digital filter of a local audio processing system, the audio signals to reduce distortions in the audio signals due to the microphone being separated from the local user'"'"'s mouth and in physical contact with the head when the earpiece is mounted at the local user'"'"'s ear, wherein the distortions are caused by one of reverberation signals that reflect off the cheek of the local user and sounds from the local user'"'"'s mouth that become out of phase at the microphone, wherein the digital filter is implemented as a stackable driver on a computer processor; and

(c) transmitting, with the local audio processing system, the filtered audio signals to a remote audio processing system for playback to a remote user.

26. A system for processing audio signals, comprising:

(a) an earpiece comprising a microphone for generating audio signals corresponding to sounds emanating from a local user having a head having a mouth, an ear, and a cheek between the mouth and ear; and

(b) a local audio processing system comprising a digital filter implemented as a stackable driver on a computer processor, wherein the local audio processing system is for filtering the audio signals with the digital filter to reduce distortions in the audio signals due to the microphone being separated from the local user'"'"'s mouth and in physical contact with the head when the earpiece is mounted at the local user'"'"'s ear, wherein the distortions are caused by one of reverberation signals that reflect off the cheek of the local user and sounds from the local user'"'"'s mouth that become out of phase at the microphone, and the local audio processing system is for transmitting the filtered audio signals to a remote audio processing system for playback to a remote user.