Echo Cancellation Using Delayed Receive Signal Injection
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Solution Overview
Problem
Echo occurs between receive and send paths in electronic devices with microphones and speakers, causing interference in audio signals.
Innovation Solution
A device comprising an echo estimator engine, a subtractor engine, a delay buffer engine, and an adder engine to determine and subtract estimated echo from the send signal, using a delayed attenuated portion of the receive signal to enhance convergence in a feedback loop.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If echo cancellation is implemented using traditional methods, then echo reduction is achieved, but convergence speed is slow and system complexity increases
Solution Approach 1:
The echo cancellation system is segmented into distinct functional engines: a delay buffer engine that manages delayed receive signals, an adder engine that combines signals, and an echo estimator engine that processes the combined signal. This segmentation allows each component to perform a specific function efficiently, reducing overall system complexity while maintaining effectiveness.
Solution Approach 2:
The delay buffer engine performs preliminary action by pre-processing the receive signal through buffering and attenuation before it reaches the adder engine. This preliminary processing prepares the signal in advance, enabling faster convergence of the echo estimator without requiring complex real-time processing, thus reducing system complexity.
2Speed
If delayed attenuated portion of receive signal is added to send signal, then convergence speed improves, but device complexity increases
Solution Approach 1:
The adder engine merges the delayed attenuated receive signal with the send signal in a unified processing path. This combining of signals allows the echo estimator to work with a pre-combined input, simplifying the overall architecture and reducing device complexity while maintaining fast convergence through the preliminary signal preparation.
Data Source
AI summary
A device, system and method for cancelling echo at electronic devices are provided. The device comprises: a send path comprising a send input and output; a receive path comprising a receive input and output; an echo estimator engine that determines an estimate of echo, on the send path; a subtractor engine subtracts the estimated echo from a send signal received at the send input; a delay buffer engine; and an adder. The delay buffer engine provides, to the adder engine, a delayed-attenuated portion of a receive signal, received at the receive input, delayed by a given delay period corresponding to at least a delay of the echo between the receive path and the send input. The adder engine adds the delayed-attenuated portion to the send signal. The echo estimator engine determines the estimated echo using at least the delayed-attenuated portion of the receive signal added to the send signal.