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US 7,925,031 B2Granted
Audio system with feedback detection means
AssigneeOticon A/S
InventorsThomas Bo Elmedyb, Johan Hellgren
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Abstract
The invention concerns an audio system comprising a microphone, audio signal processing means, an output transducer and mans for detecting a possible feedback tone and the corresponding frequency of the feedback tone in the audio system between the output transducer and the microphone. According to the invention means for counteracting feedback are provided. Further, mans are provided for changing the phase of the audio signal at a given frequency.
Claims16
An audio system, comprising:
- a microphone capturing an audio signal;
- an audio signal processor;
- an output transducer;
- a feedback tone detector which detects a possible feedback tone and a corresponding frequency of the possible feedback tone in the audio system between the output transducer and the microphone;
- a feedback counteracting unit configured to counteract the feedback;
- a controller configured to change the phase of the audio signal at a given frequency by a predefined amount of phase change whenever the feedback tone detector detects a possible feedback in the audio system at the given frequency;
- and a comparator configured to compare the frequency of the detected possible feedback tone before the phase change by the controller, to the frequency of the detected possible feedback tone while the phase of the audio signal is changed by the controller, wherein the controller is further configured to determine whether the possible feedback tone detected by the feedback tone detector is caused by acoustic feedback based on a comparison result of the comparator, the controller is further configured to change the phase of the audio signal back to its original value after the controller completes the determination of whether the possible feedback tone is caused by acoustic feedback.
4 more elements
A method for detecting acoustic feedback in an audio system, comprising:
- capturing an audio signal by a microphone;
- processing the audio signal in an audio processor;
- serving the processed audio signal at an output transducer;
- detecting a possible feedback tone along with a corresponding frequency of the possible feedback tone in the audio system between the output transducer and the microphone;
- changing the phase of the audio signal served at the output transducer at a given frequency by a predefined amount upon the detection of a possible feedback tone at the given frequency;
- comparing the frequency of the possible feedback tone before the phase change, to the frequency of the possible feedback tone while the phase of the audio signal is changed by the predetermined amount;
- determining whether acoustic feedback at the given frequency is present based on a result of the comparing;
- and changing the phase of the audio signal back to its original value after it is determined whether acoustic feedback is present.
5 more elements
Dependencies are inferred from the claim text.