| Patent application number | Description | Published |
|---|
| 20090265169 | Techniques for Comfort Noise Generation in a Communication System - A technique of operating a communication device includes dividing a frequency band associated with a background noise signal into respective sub-bands. Respective individual level estimates for each of the respective sub-bands are then determined. A total level estimate for the background noise signal is determined. Finally, a comfort noise signal (whose characteristics are based on the respective individual level estimates and the total level estimate) is provided. | 10-22-2009 |
| 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 |
| 20110013766 | METHOD AND APPARATUS HAVING ECHO CANCELLATION AND TONE DETECTION FOR A VOICE/TONE COMPOSITE SIGNAL - A system includes receive and send inputs, an adaptive filter, a combiner, a non-linear processor, and a tone detector. The receive input receives a first signal having first voice and first tone information. The send input receives a second signal having echo information, second tone information, and second voice information. The adaptive filter has an input coupled to the receive input, and an output. The combiner has a first input coupled to the send input, a second input coupled to the output of the adaptive filter, and an output providing an intermediate signal. The nonlinear processor has an input coupled to the output of the combiner and an output for providing an output signal for obtaining the second voice. The tone detector is coupled to the output of the combiner and detects the second tone in the intermediate signal prior to the intermediate signal being processed by the nonlinear processor. | 01-20-2011 |
| 20110064213 | Time Domain Adaptive Filter Bank for Network Echo Reduction or Cancellation - In one or more embodiments, an echo reduction system can include multiple adaptive filters operable to provide estimated echo replicas based on received signal information coupled to respective multiple adders that can combine a send signal and outputs of the respective adaptive filters and can provide respective output combinations to a filter selector. The filter selector can select from the outputs of the adders and provide a selected output as output for the echo reduction system. In one or more embodiments, the filter selector can control signal processing of the filters by providing control signal to the adaptive filters, where the control signals can indicate to ones of the adaptive filters to pause or continue signal processing. In one or more embodiments, the echo reduction system can include at least one delay unit that can delay receive signal information to at least one of the adaptive filters. | 03-17-2011 |
| Patent application number | Description | Published |
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| 20080205633 | Estimating delay of an echo path in a communication system - Methods and corresponding systems for reducing an echo signal include assigning a subsegment delay to each of a plurality of subsegment adaptive filters. A send signal and a delayed receive signal are coupled to each of the subsegment adaptive filters, wherein the delayed receive signal is delayed according to a respective subsegment delay. A set of filter coefficients in each of the subsegment adaptive filters are adapted, in parallel, to correspond to a respective subsegment impulse response of a connected system. Each set of filter coefficients is analyzed to produce a pure delay, and the pure delay is used to delay the receive signal for a main adaptive filter. An echo signal replica is produced using the main adaptive filter and an error signal. The echo signal replica is subtracted from the send signal to produce the error signal. | 08-28-2008 |
| 20090060167 | Adaptive filter for use in echo reduction - Methods and corresponding systems in an adaptive filter include calculating a signal estimator output using filter coefficients, and calculating an error signal. Next, a coefficient threshold is determined. Thereafter, for each filter coefficient, a first step size is assigned to filter coefficients with a magnitude less than the coefficient threshold, and a second step size is assigned to filter coefficients with a magnitude greater than or equal to the coefficient threshold. Finally, the filter coefficients are updated using the first and second step sizes and the error signal. The coefficient threshold can be selected as the average of the magnitudes of the filter coefficients. Alternatively, the coefficient threshold can be selected as the Mth largest of the filter coefficients ranked in order of magnitude. In one embodiment, the first step size can be less than one and the second step size can be greater than one. | 03-05-2009 |
