Digital Audio Waveform Correction for High-Resolution Sampling

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Solution Overview

Problem

Current methods for converting CD audio signals to high-resolution audio signals do not adequately enhance sound quality, as they fail to effectively improve the frequency band and auditory perception beyond the limitations of CD audio signals.

Innovation Solution

A digital audio processing apparatus and method that includes waveform correction processors to calculate local extrema, detect sample intervals, and apply correction values to adjacent samples, enhancing the sampling frequency conversion process to improve sound quality by adding and subtracting correction values based on predetermined coefficients.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If CD audio signals are converted to high-resolution audio signals using conventional methods, then the sampling frequency is increased, but the sound quality and auditory perception are not adequately enhanced

Engineering Contradiction:
Improvesampling frequencyVSAvoidsound quality
Core Design Contradiction:
SpeedVSManufacturing precision

Solution Approach 1:

The patent applies preliminary waveform correction to the input audio signal before sampling frequency conversion. The waveform correction processor corrects distortion components in advance by calculating correction values based on local extrema and their surrounding samples, ensuring that the signal is optimally prepared for the conversion process, thereby improving the effectiveness of the sampling frequency increase on sound quality

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent introduces a waveform correction processor as an intermediary component between the input signal and the sampling frequency converter. This intermediary processes the signal by adding correction values to samples around local extrema, effectively mediating the transition from CD quality to high-resolution quality and enhancing the overall conversion result

Inventive Principle:
Principle #24Intermediary (Mediator)

2Quantity of substance

If the sampling frequency is increased to expand the frequency band, then high-resolution audio signals are generated, but the auditory perception and sound quality improvement is insufficient

Engineering Contradiction:
Improvefrequency bandVSAvoidauditory perception
Core Design Contradiction:
Quantity of substanceVSManufacturing precision

Solution Approach 1:

The patent applies local quality correction by focusing waveform correction on specific regions around local extrema in the audio signal. By calculating correction values only for samples surrounding local maximum and minimum points, the method selectively improves critical regions of the waveform that most impact auditory perception, rather than uniformly processing the entire signal

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent changes the waveform parameters by adding correction values to the audio signal samples. The correction values are calculated based on the difference between adjacent samples and multiplied by predetermined coefficients, effectively modifying the signal parameters to enhance sound quality and auditory perception in the expanded frequency band

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3211639B1Digital sound processing device, digital sound processing method, digital sound processing program
Publication Date: 2018.10.31 JVC KENWOOD CORP
  • EP3211639B1 patent drawingFigure 1
  • EP3211639B1 patent drawingFigure 2
  • EP3211639B1 patent drawingFigure 3

AI summary

A waveform correction processor (10) corrects the waveform of a first digital audio signal (a CD signal, for example) having a first sampling frequency. A bit depth and sampling frequency converter (50) converts the first digital audio signal with the waveform corrected by the first waveform correction processor to a second digital audio signal (a high-resolution digital audio signal, for example) having a second sampling frequency, which is higher than the first sampling frequency. The waveform correction processor (20) corrects the waveform of the second digital audio signal.