Adaptive Filter Coefficient Update for Acoustic Echo Cancellation
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Solution Overview
Problem
Conventional noise elimination techniques in two-way call systems require excessive computational resources, limiting their efficiency in reducing acoustic echo and improving call quality.
Innovation Solution
A sound pick-up device with an adaptive filter that generates an estimated noise signal from a reference signal, a signal generator to produce a noise elimination signal, and a coefficient update unit that updates the filter coefficients only at specific signal sample positions identified by an identification unit where the noise elimination signal has a maximum absolute value, reducing the number of coefficient updates and thus the computational load.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the filter coefficient is updated at every signal sample position, then the noise elimination accuracy is improved, but the computational load increases
Solution Approach 1:
The patent applies partial action by updating the filter coefficient only at selected signal sample positions where the noise elimination signal has maximum absolute value, rather than at every sample position. This selective approach maintains adequate noise elimination accuracy while significantly reducing the computational load associated with continuous coefficient updates.
Solution Approach 2:
The patent implements local quality by identifying specific signal sample positions (where |noise elimination signal| is maximum) and performing coefficient updates only at these localized positions. This creates a non-uniform update strategy that concentrates computational resources at critical moments when noise cancellation is most needed, rather than uniformly distributing updates across all sample positions.
2Adaptability or versatility
If the filter coefficient is updated frequently, then the adaptability to changing noise conditions is improved, but the processing time increases
Solution Approach 1:
The patent implements periodic action by updating the filter coefficient at regularly occurring signal sample positions determined by the maximum absolute value criterion. Rather than continuous updates, the system performs updates at discrete, periodically selected moments when the noise signal is most prominent, balancing adaptability with processing efficiency.
Solution Approach 2:
The system performs coefficient updates only partially—at selected signal sample positions rather than all positions—maintaining adaptability to noise changes while reducing the total number of update operations and associated processing time.
Data Source
AI summary
A sound pick-up device includes an adaptive filter configured to generate, from a reference signal, an estimated noise signal indicating a component of a noise signal contained in an input signal, a noise elimination signal generator configured to generate a noise elimination signal by subtracting the estimated noise signal from the input signal, a filter coefficient update unit configured to update a filter coefficient of the adaptive filter using the noise elimination signal, and a sample position identification unit configured to identify at least one signal sample position among a plurality of signal sample positions from a signal sample position where the noise elimination signal has a maximum absolute value to a signal sample position where the noise elimination signal has an absolute value that is largest at a predetermined order, in which the filter coefficient update unit updates the filter coefficient at the at least one signal sample position.