Audio Signal Processing Apparatus Using Half-Wave Correction
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Solution Overview
Problem
Existing audio signal processing methods, such as those described in Japanese patent application P2002-169597A, face issues with sound quality distortion due to excessive or insufficient correction in different frequency ranges, leading to feelings of sound distortion, resonance shortage, and localization emphasis problems in audio signals.
Innovation Solution
An audio signal processing apparatus and computer program that utilize tables with coefficients and corrective values to detect sample numbers and correct audio signals by adjusting coefficients based on detected sample numbers and differences between successive samples, optimizing sound quality by applying specific weighting coefficients to each sample in the audio signal processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If waveform correction is applied to improve sound quality, then sound quality is improved, but sound quality distortion occurs due to excessive or insufficient correction in different frequency ranges
Solution Approach 1:
The patent applies different correction strengths based on the half-wave frequency characteristics. For high-frequency continuous waves (prone to distortion), weaker correction is applied. For low-frequency complex waves (needing resonance enhancement), stronger correction is applied. This local differentiation of correction intensity resolves the contradiction between improving sound quality and avoiding sound quality distortion.
Solution Approach 2:
The correction coefficient is dynamically adjusted based on the detected half-wave frequency. The system automatically varies the correction strength according to the instantaneous frequency characteristics of the audio signal, transitioning between different correction modes to optimize sound quality while preventing distortion across varying frequency ranges.
2Manufacturing precision
If correction coefficients are increased to emphasize resonance in complex waves, then resonance is enhanced, but distortion occurs in high-intensity continuous waves
Solution Approach 1:
The patent selectively applies strong correction only to half-waves identified as complex waves (lower frequency range), while applying weak correction to continuous waves (higher frequency range). This spatial-temporal differentiation ensures resonance enhancement where needed without introducing distortion where harmful.
Solution Approach 2:
The correction coefficient parameter is changed based on the half-wave frequency parameter. When the frequency indicates a complex wave, the correction coefficient is increased to enhance resonance. When the frequency indicates a continuous wave, the correction coefficient is decreased to prevent distortion. This parameter adaptation resolves the contradiction.
3Manufacturing precision
If waveform correction is applied to improve localization in complex waves, then localization is enhanced, but sound quality distortion occurs
Solution Approach 1:
The patent enhances localization by applying strong correction specifically to complex waves (lower frequency half-waves) while avoiding strong correction on continuous waves. This selective localization enhancement improves spatial perception for complex sounds without distorting continuous sound fields.
Data Source
AI summary
An audio signal processing apparatus includes first and second tables. The first table has coefficients. The second table has corrective values for correction of the coefficients in the first table. The corrective values are assigned to different sample numbers in at least two successive half-wave signal portions. Detection is made as to a sample number in a corrected-object half-wave portion of a digital audio signal and a sample number in a half-wave portion of the digital audio signal which precedes the corrected-object half-wave portion. The coefficients in the first table are corrected into correction-resultant coefficients in response to the detected sample numbers while the corrective values in the second table are used. Samples in the corrected-object half-wave portion of the digital audio signal are corrected in response to the correction-resultant coefficients.