High-Frequency Audio Interpolation via Dynamic Bandwidth Filtering
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Solution Overview
Problem
Existing high-frequency interpolation devices increase processing load and cost by doubling the sampling frequency, and fail to maintain continuous frequency characteristics due to varying audio source types and reproduction positions.
Innovation Solution
A high-frequency interpolation device that adjusts the interpolation signal's frequency conversion based on the audio signal's frequency band, using frequency analysis and filtering to generate a continuous spectrum without increasing the sampling rate, thereby reducing processing load and enhancing sound richness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If up-sampling is performed for a predetermined upper limit frequency of the audio signal, then high-frequency interpolation is achieved, but the sampling frequency doubles to 88.2 kHz or 192 kHz, increasing processing load and device cost
Solution Approach 1:
The patent changes the parameter of sampling frequency from doubled values (88.2 kHz, 192 kHz) back to the original frequency (44.1 kHz). This is achieved by performing down-sampling after up-sampling and frequency conversion, thereby reducing processing load while maintaining interpolation quality through frequency band adjustment
Solution Approach 2:
The patent dynamically adjusts the frequency band of the interpolation signal based on the original audio signal's characteristics. By making the frequency conversion amount variable rather than fixed, the system adapts to different audio sources and reproduction positions, maintaining spectral continuity without requiring increased sampling rates
2Manufacturing precision
If up-sampling is performed for a predetermined upper limit frequency of the audio signal, then high-frequency interpolation is achieved, but the device cost increases due to higher processing requirements
Solution Approach 1:
The patent changes the parameter of sampling frequency from doubled values (88.2 kHz, 192 kHz) back to the original frequency (44.1 kHz). This is achieved by performing down-sampling after up-sampling and frequency conversion, thereby reducing processing load while maintaining interpolation quality through frequency band adjustment
3Ease of operation
If fixed up-sampling is performed without considering audio source variations, then processing is simplified, but the spectrum becomes discontinuous in frequency characteristics, reducing interpolation effect
Solution Approach 1:
The patent dynamically adjusts the frequency band of the interpolation signal based on the original audio signal's characteristics. By making the frequency conversion amount variable rather than fixed, the system adapts to different audio sources and reproduction positions, maintaining spectral continuity without requiring increased sampling rates
Solution Approach 2:
The patent uses frequency band detection of the original audio signal to determine the appropriate frequency conversion amount for interpolation. This feedback mechanism ensures that the interpolation signal's frequency characteristics continuously match the original signal, preventing spectral discontinuities while maintaining processing efficiency
Data Source
AI summary
It is possible to generate an interpolation signal in which spectrum in frequency characteristics develops in a continuous manner according to a reproduced music without increasing the sampling rate (sampling frequency) in up-sampling processing. A high-frequency interpolation device 1 includes: a frequency band determination section 2 that determines a bandwidth type of an audio signal as a frequency band determination value preset for each bandwidth according to the frequency characteristics of the audio signal; and an interpolation signal generation section 3 that selects a filter coefficient of a high-pass filter in accordance with the frequency band determination value 2, performs filtering for the audio signal by using the high-pass filter having the selected filter coefficient, and generates a high-frequency interpolation signal for the audio signal.