Audio Signal Processing Device for Low-Range Emphasis
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Solution Overview
Problem
Conventional audio signal processing devices cause nonlinear distortion across a wide frequency band due to nonlinear gains, deforming sound quality of components other than low-range and high-range components, particularly in compression-encoded audio signals.
Innovation Solution
An audio signal processing device that detects the fundamental period of an input audio signal, generates a square wave with a period twice that of the fundamental frequency, and adds it to the input signal after amplitude correction, to restore the low-range component and achieve a powerful low-range emphasis effect without affecting middle- and high-range components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If nonlinear gain is assigned to the input audio signal to improve low-range component, then low-range emphasis effect is achieved, but nonlinear distortion occurs over wide frequency band and sound quality of other components is deformed
Solution Approach 1:
The invention segments the audio signal processing by separating low-range component restoration from other frequency components. It detects fundamental period to identify only low-frequency components and generates supplemental low-range signals through square wave generation at twice the fundamental frequency, while leaving middle- and high-range components unmodified. This segmentation allows low-range emphasis without applying nonlinear distortion to the entire frequency spectrum.
Solution Approach 2:
The invention applies local quality by targeting only the low-range frequency components for enhancement while preserving the original quality of other frequency bands. The square wave generation and addition process is localized to frequencies related to the fundamental period, ensuring that nonlinear processing is confined to the low-range spectrum where it is needed, while middle- and high-range components maintain their original linear quality.
2Quantity of substance
If compression encoding is applied to reduce storage capacity or communication amount, then data efficiency is improved, but low-range component impact and sound depth are reduced
Solution Approach 1:
The invention applies preliminary action by detecting the fundamental period of the compressed audio signal and proactively generating supplemental low-range components through square wave generation. This preliminary restoration of low-frequency information, based on periodicity detection, compensates for the low-range component loss that occurred during compression encoding, thereby restoring impact and depth without requiring uncompressed data.
3Power
If nonlinear gain processing is applied to restore low-range component, then low-range emphasis is achieved, but middle- and high-range components are deformed
Solution Approach 1:
The invention segments frequency processing by using fundamental period detection to identify and process only low-range components. The square wave generation at twice the fundamental frequency and subsequent addition to the input signal creates low-range enhancement that is spectrally separated from middle- and high-range components, preventing deformation of those frequency bands while restoring low-range impact.
Solution Approach 2:
The invention extracts only the low-range component information needed for restoration by detecting fundamental period and generating square waves at specific frequencies. This extraction approach isolates the restoration process to low-frequency domain, taking out the necessary low-range elements from the compressed signal while leaving middle- and high-range components untouched and preserving their original quality.
Data Source
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AI summary
An audio signal processing device 100 includes a period detecting unit 102 for detecting the fundamental period of an input audio signal 101; a square wave generating unit 106 for generating, according to the fundamental period the period detecting unit 102 detects, a square wave 107 whose period is an integer multiple of the fundamental period; an amplitude correction coefficient generating unit 103 for calculating an amplitude correction coefficient 109 approximately equal and proportional to the intensity of the input audio signal 101; a first multiplier 108 for generating an amplitude-corrected square wave 110 by multiplying the square wave 107 by the amplitude correction coefficient 109; and an adder 104 for adding the amplitude-corrected square wave 110 to the input audio signal 101.