Audio Signal Processing Non-Linearity Correction
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Solution Overview
Problem
Existing audio signal processing methods do not effectively address the non-linearity of electroacoustic transducers and the psychoacoustic characteristics of the human ear, leading to inconsistent sound quality and perception across different audio chains.
Innovation Solution
The method involves approximating the psychoacoustic characteristics of the human ear using a fifth-degree polynomial function and adding non-linear elements in the audio chain to correct the non-linearity of electroacoustic transducers, specifically using quadratic and hyperbolic functions to reduce distortions and enhance sound quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If non-linear elements are added to correct transducer non-linearity, then sound quality improves, but device complexity increases
Solution Approach 1:
The patent introduces an intermediary processing stage that models the human ear's non-linear psychoacoustic characteristics and uses this model to generate correction signals. The intermediary system includes polynomial function generators and signal combiners that mediate between the raw audio signal and the final corrected output, allowing complex non-linearity correction without requiring complete redesign of the audio chain.
Solution Approach 2:
The patent changes the parameters of the audio signal by applying polynomial transformations (quadratic, cubic, and higher-order terms) to introduce controlled non-linearities. By adjusting the coefficients of these polynomial functions, the system dynamically modifies signal parameters to compensate for transducer non-linearity and match human perceptual characteristics.
2Measurement precision
If psychoacoustic non-linearities are incorporated, then acoustic image quality improves, but processing complexity increases
Solution Approach 1:
The patent segments the psychoacoustic correction process into distinct functional blocks: polynomial function generators for different order terms (quadratic, cubic, etc.), separate processing paths for different non-linear components, and individual combiners for each harmonic component. This segmentation allows complex psychoacoustic modeling to be implemented as a series of manageable, independent processing stages.
Solution Approach 2:
The patent performs preliminary action by pre-calculating and storing polynomial coefficients that represent human ear psychoacoustic characteristics. These pre-computed correction parameters are then applied to the audio signal, avoiding the need for real-time complex psychoacoustic modeling and reducing processing complexity during actual audio reproduction.
3Reliability
If polynomial approximation of psychoacoustic characteristics is used, then non-linearity correction improves, but computational requirements increase
Solution Approach 1:
The patent applies partial action by selectively implementing only the most significant polynomial terms (quadratic, cubic, and selected higher-order terms) rather than computing all possible non-linear components. This selective approach provides sufficient non-linearity correction for perceptually important frequency ranges while avoiding unnecessary computational overhead from less significant higher-order terms.
Data Source
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AI summary
The present invention relates to a method and device/apparatus for an audio signal processing in an audio chain, the method and apparatus that correct a non-linearity of electroacoustic transducers in the audio chain taking into consideration also a non-linear psychoacoustical characteristics of the human ear by adding non-linearities in the audio chain in a controlled manner, in order to obtain a better acoustic image and more details when reproducing a sound by using approximation of the quadratic and a fifth degree polynomial function in some range. According to the present invention, the method comprises approximating by a non-linear fifth degree polynomial function of the psychoacoustical characteristics of the human ear and adding of at least one non-linear element (4) in front of at least one electroacoustic transducer in the audio chain, whereby the non-linear element (4) has a function to add a non-linearity in the audio chain that corrects the non-linearity of at least one electroacoustic transducer and/or the non-linearity of the approximated psychoacoustical characteristic of the human ear for a pressure change by the human ear up to ρΔ. An audio signal processing apparatus (19) of the present invention comprises at least one non-linear element (4) in an audio chain that has the function of adding non-linearity to an audio chain that corrects the non linearity of at least one electroacoustic transducer and/or the non-linearity of the approximate psychoacoustical characteristic of the human ear for the pressure change by the human ear to ρΔ. The present method and the apparatus (19) reduce limitations of the electroacoustic transducers as well as the human ear by adding non-linearities that, ultimately reduce non-linearities of the entire audio chain with the human ear, i.e. adding non-linearities in the audio chain so that an audio chain characteristic reduces the non-linearity of the human ear polynomial approximation to the pressure change ρΔ = ±1 Pa.