Method for suppressing speaker activation in a portable communication device operated in a speakerphone mode

• US 6,138,040 A
• Filed: 07/31/1998
• Issued: 10/24/2000
• Est. Priority Date: 07/31/1998
• Status: Expired due to Term

• Current Assignee: Google Technology Holdings LLC (Alphabet Inc.)
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Nicholls, Richard Brent, Koenigsman, Scott David
• Primary Examiner(s): Hunter, Daniel S.
• Assistant Examiner(s): WYCHE, MYRON
• Application Number:
  US09/127,692
• Time in Patent Office: 816 Days
• Field of Search: 455/569, 455/79, 455/63, 379/388, 379/389, 379/390
• US Class Current: 455/569.1
• 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

Abstract

In a portable communication device (100) operated in a speakerphone mode, when no speech is present in either the outbound signal received from a communication system, the speaker (114) of the communication device is muted and the microphone (120) activated. When speech is detected in an inbound signal (202, 204, 206), and speech is also subsequently detected in the outbound signal (214), the speaker is left inactivated and the microphone kept in an activated state. To determine if speech is present in the inbound signal, the inbound signal is voided, providing a succession of frames (206), each frame having a frame energy parameter and a background noise parameter (208). If the frame energy of a given frame sufficiently exceeds the an average background noise value for the given frame, then speech is declared present. To smooth this half duplex operation, a timer may be used so that brief periods of silence or fricative parts of speech do not result in a revocation of the declaration of speech in the inbound signal.

Claims

1. A method for suppressing speaker activation in a portable communication device operated in a speakerphone mode, comprising the steps of:

receiving an outbound audio signal from a wireless source;

determining that the outbound audio signal does not contain speech information;

muting the speaker;

receiving an inbound audio signal at a microphone of the portable communication device;

vocoding the inbound audio signal to provide an inbound vocoded signal comprising of a succession of frames, each frame of the succession of frames having a frame energy value and a background noise value;

calculating an average background noise value for each frame of the succession of frames;

calculating a staggered average value of the frame energy;

comparing the staggered average value of the frame energy with the average background noise value;

determining that speech is present in a given frame of the succession of frames if the staggered average value of the frame energy is sufficiently greater then the average background noise value; and

preventing activation of the speaker while performing the step of determining that speech is present in the inbound audio signal while, subsequent to performing the step of determining, detecting speech information in the outbound audio signal.

2. A method for suppressing speaker activation as defined in claim 1, wherein in the step of vocoding, the background noise value is a comfort noise value.

3. A method for suppressing speaker activation as defined in claim 1, wherein the step of preventing activation is performed for a preselected period of time after speech is no longer present in the inbound audio signal.

4. A method for activating a speaker in a portable communication device operated in a speakerphone mode, the speaker normally muted, the method comprising the steps of:

vocoding an inbound audio signal to provide a succession of frames, each frame of the succession of frames having a frame energy value and a background noise value;

calculating an average background noise value for each frame of the succession of frames;

calculating a staggered average value of the frame energy;

detecting an inbound voice content in the inbound audio signal when the staggered average value of the frame energy exceeds the average background noise value;

receiving a radio frequency signal;

detecting an outbound voice signal in the radio frequency; and

playing the outbound voice signal over the speaker only when not performing the step of detecting an inbound voice signal and while performing the step of detecting an outbound voice signal.

5. A method for activating a speaker as defined in claim 4, wherein the step of detecting an inbound voice content comprises determining that the frame energy of a given frame of the succession of frames is higher than the average background noise value corresponding to the given frame.

6. A method for activating a speaker as defined in claim 4, wherein in the step of vocoding, the background noise value is a comfort noise value.

7. A method for activating a speaker as defined in claim 4, wherein, in the step of playing the outbound voice signal, if the inbound voice content is detected prior to detecting the outbound voice content, waiting a preselected period of time after the inbound voice signal is detected before playing the outbound voice signal.