| Class / Patent application number | Description | Number of patent applications / Date published |
|---|
| 379406050 | Residual echo cancellation | 9 |
| 20080253553 | Filter bank optimization for acoustic echo cancellation - A communications device is presented for providing bi-directional audio communications between a near-end user and a far-end user via a bidirectional communications channel. The communications device includes an adaptive echo canceller receiving a near-end audio signal and a far-end audio signal and providing an echo-canceled near-end audio signal for transmission to the far-end user via the communications channel. The adaptive echo canceller includes a first bank of analysis filters for filtering the near-end audio signal, a second bank of analysis filters for filtering the far-end audio signal, and a bank of synthesis filters for filtering sub-band echo-canceled signals generated within the adaptive echo canceller. The first and second filter banks have a frequency response optimized to reduce echo residual gain. | 10-16-2008 |
| 20090168993 | Echo Canceler - A state deciding unit | 07-02-2009 |
| 20090323924 | ACOUSTIC ECHO SUPPRESSION - Sound signals captured by a microphone are adjusted to provide improved sound quality. More particularly, an Acoustic Echo Reduction system which performs a first stage of echo reduction (e.g., acoustic echo cancellation) on a received signal is configured to perform a second stage of echo reduction (e.g., acoustic echo suppression) by segmenting the received signal into a plurality of frequency bins respectively comprised within a number of frames (e.g., 0.3 s to 0.5 s sound signal segments) for a given block. Data comprised within respective frequency bins is modeled according to a probability density function (e.g., Gaussian distribution). The probability of whether respective frequency bins comprise predominantly near-end signal or predominantly residual echo is calculated. The output of the acoustic echo suppression is computed as a product of the content of a frequency bin in a frame and the probability the frequency bin in a frame comprises predominantly near-end signal, thereby making near-end signals more prominent than residual echoes. | 12-31-2009 |
| 20090323925 | System and Method for Telephone Based Noise Cancellation - A system and method for enhancing communications through a phone. A voice communication is received from a user of the phone. A secondary signal is received from an environment in proximity to the phone. The secondary signal is processed to determine an inverse signal in response to receiving the secondary signal. The inverse signal is combined with the voice communication and the secondary signal to destructively interfere with the secondary signal for allowing a receiving party to more effectively communicate with the user. | 12-31-2009 |
| 20100034373 | ECHO CANCELLER WITH HEAVY DOUBLE-TALK ESTIMATION - In a data processing system, a method includes receiving samples of a send path input signal (Sin) and samples of a receive path input signal (Rin); in response to receiving each sample of the send path input signal, providing a double-talk indicator to indicate whether or not double-talk has been detected; using the double-talk indicator to determine a double-talk density within a predetermined number of samples of the send path input signal or the receive path input signal; and using the double-talk density to provide a heavy double-talk indicator which indicates whether or not heavy double-talk has been detected. In response to the heavy double-talk indicator indicating that heavy double-talk has been detected, a heavy double-talk mode may be entered. | 02-11-2010 |
| 20100246804 | MITIGATION OF ECHO IN VOICE COMMUNICATION USING ECHO DETECTION AND ADAPTIVE NON-LINEAR PROCESSOR - Architecture that mitigates echo in voice communications using echo detection and adaptive management of attenuation by a non-linear processor (NLP). Suppression values provided by the NLP are determined based on echo detection and retained on a case-by-case basis to automatically increase or decrease the attenuation as needed. Feedback is incorporated that where the controls for the NLP attenuation is given by the amount of echo that remains, and this in turn affects the amount of echo that remains. | 09-30-2010 |
| 20120294437 | AUTOMATIC GAIN CONTROL FOR TELE-PRESENCE VOICE ECHO CANCELLERS - In a closed loop acoustic system with forward and return paths, gain is controlled with different instantiations of a common gain control engine on each path. The gain control engine computes a first gain based on near-end signal levels, computes a second gain based on the output of the gain control engine, computes a third gain based on a howling condition, and computes a final gain as the product of the first, second and third gains. | 11-22-2012 |
| 20140355751 | Systems and Methods for Echo Reduction - Systems and methods are provided for echo reduction. For example, first audio data associated with a current time unit is obtained, the first audio data being generated by an audio-acquisition device of a receiver based on at least information associated with a first audio signal acquired by the audio-acquisition device and a second audio signal output from an audio-playback device of the receiver, the second audio signal being output from the audio-playback device of the receiver based on at least information associated with second audio data transmitted previously by a sender before the current time unit; third audio data transmitted by the sender during a second time unit preceding the current time unit is obtained; and fourth audio data is obtained by performing echo reduction on the first audio data based on at least information associated with the third audio data. | 12-04-2014 |
| 20150086006 | ECHO SUPPRESSOR USING PAST ECHO PATH CHARACTERISTICS FOR UPDATING - In an echo suppressor, a frequency bin component detector compares a far-end signal amplitude spectrum with a threshold value for each frequency bin to determine whether or not each frequency bin includes a frequency component. A frequency bin echo path characteristic estimator uses the far-end signal amplitude spectrum in the frequency bins determined to have a frequency component by the frequency bin component detector and the near-end input signal amplitude spectrum of corresponding frequency bins to estimate the echo path characteristics of the frequency bins. An estimated echo signal calculation-and-echo suppressor section calculates estimated echo signals based on the echo path characteristic in each frequency bin and the far-end signal amplitude spectrum to suppress the estimated echo signals from the near-end input signal amplitude spectrum. | 03-26-2015 |
