Echo Control Noise Pumping Reduction via Signal Copying
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Solution Overview
Problem
Conventional audio signal processing systems experience noise 'pumping' due to the suppression of echo control components, which can lead to inconsistent noise levels and increased perceptual noise effects, especially when noise suppression components are placed after echo control components in the signal path.
Innovation Solution
A method and system where a noise suppression component processes a noisy signal to generate a noise-suppressed signal, which is then analyzed by an echo control component in the frequency domain to apply echo control processing, potentially with the aid of a delay block to compensate for processing delays, thereby reducing noise pumping and maintaining consistent noise levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the echo control component processes the signal before the noise suppression component, then echo suppression is effective, but noise pumping occurs due to comfort noise replacement
Solution Approach 1:
The patent introduces an intermediary mechanism where the noise suppression component analyzes the original noisy signal separately from the echo control processed signal. This allows the NS component to maintain its noise suppression decisions based on the true noise characteristics rather than being misled by comfort noise, effectively mediating between EC and NS operations to prevent noise pumping while preserving echo suppression.
Solution Approach 2:
The patent segments the signal processing into two independent pathways: one for echo control processing and another for noise suppression analysis. The NS component receives both the original noisy signal (for accurate noise analysis) and the EC-processed signal (for final output), allowing it to make suppression decisions independently of the comfort noise introduced by EC.
2Productivity
If the noise suppression component is placed after the echo control component, then echo control can process the signal early, but noise suppression effectiveness is reduced due to comfort noise interference
Solution Approach 1:
The patent creates a copy of the original noisy signal that bypasses the echo control component and is fed directly to the noise suppression component for analysis. This copy serves as a reference for accurate noise level estimation, allowing the NS component to make decisions based on true noise characteristics rather than comfort noise, thereby maintaining measurement precision while preserving processing efficiency.
3Ease of operation
If the noise suppression component analyzes the signal after echo control processing, then processing order is maintained, but noise pumping increases during echo segments
Solution Approach 1:
The patent implements a feedback mechanism where the noise suppression component continuously monitors the original noisy signal and compares it with the EC-processed signal. This feedback loop allows the NS component to detect when comfort noise is present and adjust its suppression accordingly, maintaining noise level consistency while preserving the simple processing chain structure.
Data Source
AI summary
An input signal is processed through noise suppression (NS) and echo control (EC) via a multipath model that reduces noise pumping effects while maintaining EC performance. A copy of a “noisy” input signal is sent to an EC component before the noisy signal is sent to a NS component, which processes the signal first, when there is a consistent noise level for estimation. The copy of the pre-processing noisy signal is sent to the EC component along with a “clean” or “noise-suppressed” signal output from the NS component. The EC component analyzes the noisy signal as if the EC was the first component in the signal chain to determine what actions to take. The EC component then applies these actions to the clean signal received from the NS component.