Digital Audio Processing Device Sine Wave Detection
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Solution Overview
Problem
Existing digital audio processing devices degrade sound quality when processing periodic signals of single sine waves, as they often add unwanted overtones, degrading the audio signal.
Innovation Solution
A digital audio processing device that calculates local maxima and minima in digital audio signals, detects sample intervals, and applies correction values only when the signal is not a periodic single sine wave, using a periodic signal detector to determine whether to add or subtract correction values based on predetermined coefficients.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If correction values are applied to all digital audio signals to improve sound quality, then non-sine wave signals are improved, but periodic single sine wave signals degrade due to unwanted overtones being added
Solution Approach 1:
The patent applies different processing treatments to different types of audio signals. By detecting whether a signal is a periodic single sine wave, the system applies correction values only to non-sine wave signals, giving each signal type the appropriate local treatment rather than uniform processing.
Solution Approach 2:
Instead of applying correction values to all signals and then trying to remove unwanted overtones, the patent inverts the approach by detecting sine waves and excluding them from correction processing, thereby preventing the harmful effect before it occurs.
2Manufacturing precision
If a periodic signal detector is added to selectively process signals, then sound quality for sine waves is preserved, but device complexity increases
Solution Approach 1:
The patent performs preliminary detection of periodic single sine waves before applying correction processing. This preliminary action allows the system to avoid unnecessary processing for sine wave signals, preventing the addition of unwanted overtones while maintaining efficiency.
Solution Approach 2:
The patent changes the processing parameter (application of correction values) based on the detected signal characteristics. By monitoring the periodicity parameter and signal type, the system dynamically adjusts whether to apply correction values, thereby adapting to different signal conditions.
Data Source
AI summary
A local extremum calculator detects a local maximum sample and a local minimum sample of a digital audio signal. A number-of-sample detector detects a sample interval between the local maximum sample and the local minimum sample. A difference value calculator calculates difference values between adjacent samples. A correction value calculator calculates a first correction value by multiplying the difference value between the local maximum sample and a first adjacent sample by a coefficient and calculates a second correction value by multiplying the difference value between the local minimum sample and a second adjacent sample by the coefficient. When a periodic signal detector detects that the digital audio signal is a single sine wave, an adder/subtractor does not add the first correction value to the first adjacent sample, and does not subtract the second correction value from the second adjacent sample.