Echo Cancellation Device Frequency Band Feature Analysis
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Solution Overview
Problem
Existing echo cancellation techniques fail to accurately separate noise components from echo signal components, leading to inadequate echo suppression in hands-free communication devices, particularly during double-talk states, which deteriorates call quality.
Innovation Solution
An echo cancellation device and method that suppresses echo signal components by using a voice output unit to generate a first voice signal with suppressed frequency components above a target frequency, a voice input unit to detect acoustic signals with echo components, and a filter coefficient update determination unit to adjust suppression based on feature value differences between frequency bands, ensuring accurate echo reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional echo cancellation techniques are used, then echo suppression is attempted, but noise components and echo signal components cannot be accurately separated, leading to inadequate echo suppression
Solution Approach 1:
The patent segments the acoustic signal into multiple frequency bands and processes each band separately. By dividing the frequency spectrum into different ranges, the system can apply different processing strategies to voice components (typically in specific frequency ranges) and noise/echo components (in other frequency ranges), enabling more precise separation and suppression of echo while preserving voice quality.
Solution Approach 2:
The patent applies different processing characteristics to different frequency bands. Specifically, voice frequency bands are handled with one set of processing parameters while non-voice frequency bands are handled with another set, allowing the system to optimize echo suppression locally in each frequency range rather than applying a uniform approach across the entire spectrum.
2Reliability
If the voice signal bandwidth is limited to improve echo cancellation, then echo suppression is enhanced, but the naturalness and quality of the output voice signal deteriorate
Solution Approach 1:
The patent dynamically adjusts the bandwidth and frequency characteristics of the output voice signal based on the detected voice frequency components. Rather than using a fixed bandwidth limitation, the system adapts the frequency range in real-time according to the actual voice signal characteristics, thereby maintaining natural voice quality while effectively suppressing echo in the appropriate frequency ranges.
Solution Approach 2:
The patent changes the frequency domain parameters of the output signal by selectively attenuating or removing echo components in specific frequency bands while preserving voice components. This parameter adjustment in the frequency domain allows echo suppression without significantly degrading the naturalness of the voice signal.
3Object-generated harmful factors
If frequency components above a target frequency are suppressed to reduce echo, then echo signal components are reduced, but voice components in higher frequency bands are also attenuated
Solution Approach 1:
The patent extracts and removes only the echo signal components from the acoustic signal by identifying them through frequency band analysis and comparing with the original transmitted signal. Rather than suppressing all high-frequency components, the system specifically extracts and removes echo portions while preserving voice components, thereby reducing echo without significantly affecting voice fidelity.
4Device complexity
If the echo canceller processes all frequency components uniformly, then processing simplicity is maintained, but double-talk detection accuracy deteriorates
Solution Approach 1:
The patent segments the frequency spectrum into multiple bands and processes each band independently for double-talk detection. By dividing the frequency range into voice and non-voice bands, the system can more accurately detect whether both parties are talking simultaneously (double-talk condition) in each band, improving detection accuracy without significantly increasing overall processing complexity.
Data Source
AI summary
An echo cancellation device includes an echo signal reduction processing unit that generates a transmitting signal in which an echo signal component is reduced from the acoustic signal; and a filter coefficient update determination unit that instructs the echo signal reduction processing unit to update the filter coefficient when the output voice signal corresponds to a voice section and the acoustic signal includes the echo signal component. The filter coefficient update determination unit calculates a feature value of the acoustic signal and instructs to update the filter coefficient when a difference between a first feature value of a frequency band equal to or lower than the target frequency and a second feature value of a frequency band higher than the target frequency is equal to or greater than a preset update determination threshold.