Speech Band Extension Timing Synchronization
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Solution Overview
Problem
Existing speech band extension methods result in unnatural audibility due to the improper phase relationship between the original and newly generated frequency components, leading to an unnatural feeling when hearing the wide-band audio signal.
Innovation Solution
A speech band extension device that includes band-extended audio generation, timing shift detection, adjustment, and combination means to synchronize the timing of the original and band-extended audio signals, ensuring natural audibility by adjusting the timing of the signals before combination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the original audio signal and band-extended audio signal are simply added without timing adjustment, then the device complexity is reduced, but the audibility becomes unnatural due to phase relationship issues
Solution Approach 1:
The patent applies preliminary action by detecting the timing shift between the original audio signal and band-extended audio signal before combining them. The timing shift detection means identifies the phase relationship, and the adjustment means pre-adjusts the timing of one signal relative to the other, ensuring proper phase alignment before the addition operation. This preliminary timing adjustment resolves the unnatural audibility issue while maintaining a relatively simple overall device structure.
2Manufacturing precision
If timing adjustment is performed to synchronize the original and band-extended signals, then the audibility quality is improved, but the device complexity increases due to additional detection and adjustment means
Solution Approach 1:
The patent introduces timing shift detection means and adjustment means as intermediary components between the band-extended audio generation means and the combination means. These intermediary elements specifically address the phase relationship issue by detecting timing shifts and applying appropriate adjustments, thereby improving audibility quality without requiring complete redesign of the entire signal processing system.
3Reliability
If the frequency band is extended to include low-band and high-band components, then the voice personality and speech understanding are improved, but the phase relationship between frequency components becomes misaligned causing unnatural audibility
Solution Approach 1:
The patent applies local quality by specifically addressing the phase relationship issue in the frequency domain. The timing shift detection means detects timing shifts that affect different frequency components differently, and the adjustment means applies targeted timing adjustments to align the phase relationships of low-band, mid-band, and high-band components. This localized approach to phase alignment ensures that each frequency component is properly synchronized, resulting in natural audibility and improved voice quality.
Data Source
AI summary
A speech band extension device (100), which generates an audio signal capable of realizing natural audibility after speech band extension, includes a band-extended audio generator which generates a band-extended audio signal from an original audio signal, the band-extended audio signal including components lying within a frequency band that is not included in a frequency band of the original audio signal, and an adjustment adder (20) which detects a timing shift between the original audio signal and the band-extended audio signal, adjusts timing of the original audio signal and timing of the band-extended audio signal in accordance with the detected timing shift, and combines the both signals after the adjusting of the timing, wherein the detection of the timing shift is performed, for example, using zero-crossing and cross-correlation.