Hilbert Transform Sub-band Audio Processing for Beamforming
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Solution Overview
Problem
Conventional audio-signal processing systems experience performance degradation due to frequency aliasing introduced by down-sampling in sub-band analysis/decomposition modules, which affects beamforming performance.
Innovation Solution
The implementation of Hilbert Transformation (HT) sub-band analysis/decomposition modules, which include a Hilbert Transformation module and an analysis/decomposition filter bank, reduces frequency aliasing with moderate to no increase in computational complexity, by removing negative frequency components and using frequency-shifting and down-sampling to prevent aliasing issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If down-sampling is used in sub-band analysis/decomposition modules, then computational complexity is reduced, but frequency aliasing is introduced which degrades beamforming performance
Solution Approach 1:
The patent applies preliminary action by performing Hilbert transformation on the input signal before down-sampling. This preliminary processing removes negative frequency components and prevents frequency aliasing from occurring during the subsequent down-sampling step, thereby maintaining beamforming performance while still benefiting from reduced computational complexity
Solution Approach 2:
The Hilbert transformation serves as an intermediary processing step between the input signal and the down-sampling operation. It acts as a mediator that transforms the signal into a form where down-sampling can be performed without introducing frequency aliasing, thus resolving the contradiction between computational efficiency and signal processing accuracy
2Reliability
If Hilbert Transformation is applied to remove negative frequency components, then frequency aliasing is reduced, but computational complexity increases
Solution Approach 1:
The patent changes the parameter of the signal by applying Hilbert transformation, which shifts the frequency spectrum and removes negative frequency components. This parameter change enables subsequent down-sampling to proceed without introducing frequency aliasing, achieving reliable frequency processing while the computational cost is managed through efficient implementation
Data Source
AI summary
Provided are, among other things, systems, methods and techniques for audio-signal processing. One representative embodiment includes HT sub-band analysis/decomposition modules, e.g., one for each audio channel and one for an echo reference signal. Each HT sub-band analysis/decomposition module includes a Hilbert Transformation module and an analysis/decomposition filter bank and provides sub-band outputs. Echo-cancellation modules, e.g., one for each audio channel, perform echo-cancellation processing on such sub-bands. Beamforming modules, e.g., one for each sub-band, then perform beamforming, e.g., across all audio channels. Finally, a resynthesis stage combines the different sub-band outputs in order to provide a system output signal.