Speech Waveform Alignment via Trigonometric Function Pairing
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Solution Overview
Problem
Existing speech coding methods face challenges in efficiently aligning periodic speech waveforms, particularly in the frequency domain, due to high computational complexity and the need for precise phase shifts, which can lead to poor results when encoding both periodic and non-periodic speech segments.
Innovation Solution
A method that evaluates trigonometric functions for each phase shift within a range to calculate correlation measures between periodic speech waveforms, using a technique that pairs phase shifts and reduces the number of trigonometric function evaluations, thereby simplifying the alignment process and reducing computational burden.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If cross-correlations are calculated in the frequency domain for prototype alignment, then alignment precision is improved, but computational complexity increases
Solution Approach 1:
The patent divides the frequency range into multiple segments or bins, calculating cross-correlations for each segment separately. This segmentation allows the use of simpler computational methods within each segment while maintaining overall alignment precision, thereby reducing total computational complexity compared to calculating across the entire frequency range at once.
Solution Approach 2:
The patent calculates cross-correlations only for a subset of frequency components or phase shifts rather than exhaustively computing all possible combinations. By performing partial calculations on selected frequency bins or phase shift values, the method achieves sufficient alignment precision without the full computational burden of complete frequency-domain cross-correlation.
2Measurement precision
If multiple phase shifts are evaluated to ensure accurate waveform alignment, then alignment accuracy is improved, but the number of trigonometric function evaluations increases
Solution Approach 1:
The patent combines the evaluation of multiple phase shifts by computing cross-correlations for paired phase shift values simultaneously or in an integrated manner. By merging the calculation process for multiple phase shifts into a unified computation framework, the method reduces the total number of separate trigonometric function evaluations needed while still achieving accurate alignment through multiple phase shift assessment.
Solution Approach 2:
The patent performs preliminary calculations of trigonometric functions that can be reused across multiple phase shift evaluations. By pre-computing certain trigonometric values or intermediate results that remain constant across different phase shifts, the method reduces redundant calculations and improves processing efficiency while maintaining the ability to evaluate multiple phase shifts for accurate alignment.
Data Source
AI summary
Systems, methods, and apparatus described include waveform alignment operations in which a single set of evaluated cosines and sines is used to calculate cross-correlations of two periodic waveforms at two different phase shifts.