A Robust Broadband Beamformer Design Method Based on Probability Constraints

A design method and technology of the former, which can be applied to instruments, radio wave measurement systems, etc., can solve the problems of being too conservative and expected signal attenuation, and achieve the effect of simple, intuitive, and good passband beam response performance.

CN108983201BActive Publication Date: 2022-06-17NANJING UNIV OF AERONAUTICS & ASTRONAUTICS
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Patents(China)
Current Assignee / Owner
Publication Date
2022-06-17

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Abstract

The invention discloses a design method of a robust broadband beamformer based on probability constraints, and belongs to the technical field of array signal processing. The method includes the following steps: firstly, the method transforms the probability problem into a convex optimization problem through inequality deformation; secondly, assuming that the known prior information of the microphone mismatch error is the uncertainty of each mismatch error expectation and variance is the largest The robust parameters are calculated under the boundary conditions; then, the probability selection range is determined according to the characteristics of the function of the convex function changing with the parameters; finally, a robust far-field broadband beamformer with good passband frequency invariance performance is obtained through appropriate probability parameter selection weight. Under the same error condition, the present invention not only has good robustness, but also has better passband consistency gain, which ensures that the signal will not be significantly distorted.
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Description

technical field

[0001] The invention relates to a method for designing a robust broadband beamformer based on probability constraints, and belongs to the technical field of array signal processing. Background technique

[0002] In audio and speech signal processing, the design of beamformers using microphone arrays is an important research direction. Fixed-weight beamformers are widely used because they do not depend on received data, are simple in design, easy to implement, and have good real-time performance. However, in fact, the fixed-weight beamforming design will be affected by the microphone mismatch error in the actual environment, which will lead to a substantial decrease in the performance of the fixed-weight beamformer, which not only leads to the inability to effectively suppress interference or noise, but also leads to serious attenuation of the desired signal. . Therefore, designing broadband fixed-weight beamformers with robust performance is an important res...

Examples

Embodiment 1

[0099] Comparison diagram of passband frequency invariant energy and WNG comparison between the robust design method based on probability constraints and the conventional robust design method based on stop-band constraint optimization and the conventional worst performance optimization design method under different conditions

[0100] Consider a linear array composed of M=7 array elements, the array element spacing d=0.04m, and the number of filter taps connected to each array element is L=20. Set the sampling frequency f s =8000Hz, and the considered frequency band range is [1500,3500]Hz, the angle range of the passband is [80°,100°], and the angle range of the stopband is [0°,60°]∪[120°,180° ]. The passband expected response is P d (θ p ,f)=exp{-j2πf(L-1)f s -1 / 2}, while the stopband parameter Γ sb =-6dB. For the microphone error information, we assume |E[Δa m ]|≤0.02, |E[Δd m ]|≤0.0007, |Var[Δa m ]|≤0.015, and |Var[Δd m ]|≤2×10 -6 m 2 . K=40, N p = 20. ...