Echo Suppression via Frequency-Dependent Temporal Smoothing
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Solution Overview
Problem
Existing audio devices face challenges in effectively suppressing echo during communication, particularly in environments where echo interference reduces the perceived quality of audio calls, and existing echo cancellation methods may not adequately address the varying power levels of echo in different device arrangements.
Innovation Solution
A method is introduced that models the echo path using an adaptive model based on both the outputted and received audio signals to estimate echo power, determining echo suppression gains, which are then smoothed temporally according to frequency to suppress echo in the received audio signal, ensuring minimal impact on near-end signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If echo cancellation methods are applied to suppress echo in received audio signals, then echo interference is reduced, but the complexity of signal processing increases
Solution Approach 1:
The patent applies parameter changes by using frequency-dependent smoothing of echo suppression gains. Different smoothing parameters are applied to different frequency bands, with higher frequencies receiving more smoothing than lower frequencies. This allows effective echo suppression while adapting to the varying characteristics of echo across the frequency spectrum, resolving the contradiction between suppression effectiveness and processing complexity.
Solution Approach 2:
The patent segments the audio signal into multiple frequency bands and applies different echo suppression strategies to each band. By dividing the frequency spectrum into segments (e.g., low, mid, high frequencies), the system can optimize echo suppression for each band individually, reducing overall processing complexity while maintaining effectiveness.
2Object-affected harmful factors
If frequency-dependent echo suppression is applied, then echo power reduction is improved, but near-end signal quality may deteriorate
Solution Approach 1:
The patent applies local quality by implementing frequency-dependent smoothing where different degrees of smoothing are applied to different frequency bands. Higher frequency bands receive more smoothing to suppress echo, while lower frequency bands receive less smoothing to preserve near-end signal quality. This localized approach ensures that echo suppression is optimized for each frequency region without uniformly degrading signal quality across the entire spectrum.
Data Source
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AI summary
An echo path of the echo in a received audio signal is modelled using an adaptive model to determine an adaptive model estimate of the echo. The adaptive model estimate is used to determine an estimate of the echo power of the echo in the received audio signal. The power of the received audio signal is determined. The estimate of the echo power and the determined power of the received audio signal are used to determine echo suppression gains. Temporal smoothing is applied to one or more of the echo suppression gains and the one or more smoothed echo suppression gains are used to apply echo suppression to the received audio signal, thereby suppressing the echo in the received audio signal, wherein the amount of smoothing applied to the echo suppression gains is varied according to a non-decreasing function of the frequency of the received audio signal.