Optimal active time-reversal focusing method based on iterative least square/pre-filtering

A technology of iterative least squares and time defocusing, which is applied in the direction of sound-generating devices, impedance networks, instruments, etc., can solve problems such as tailing and time-domain waveform broadening

Active Publication Date: 2012-03-14
INST OF ACOUSTICS CHINESE ACAD OF SCI
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Problems solved by technology

[0039] The purpose of the present invention is: in order to overcome the time-domain waveform broadening and smearing problems existing in the existing conventional active-time defocusing signals, thereby proposing an optimal active-time defocusing method based on iterative least squares-prefiltering

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  • Optimal active time-reversal focusing method based on iterative least square/pre-filtering
  • Optimal active time-reversal focusing method based on iterative least square/pre-filtering
  • Optimal active time-reversal focusing method based on iterative least square/pre-filtering

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Embodiment Construction

[0178] The present invention will be described in detail below in conjunction with the accompanying drawings and embodiments.

[0179] The basic idea of ​​the present invention is to use the designed iterative pre-filter to compensate the non-ideal channel autocorrelation function equivalent to the conventional active time inverse method step by step, so that it approaches the ideal Dirac-delta function, so that the active time inverse The focusing method achieves the inverse filter focusing effect in the time domain, while maintaining the spatial resolution of the conventional active time inverse focusing method. The invention eliminates the broadening and smearing problems of time-domain waveforms existing in conventional time-anti-focus signals, and is not affected by frequency response differences between elements of time-anti-array arrays, and can be applied to acoustic focusing of random arrays.

[0180] In order to better understand the present invention, the present in...

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Abstract

The invention relates to an optimal active time-reversal focusing method based on iterative least square / pre-filtering. The method comprises the following steps: 1) sending source signals by a guide sound source, and conducting the operations of receiving, time-reversal and re-sending by a time-reversal array according to the conventional active time-reversal process, so as to acquire focusing signals at the location point of the sound source, wherein the source signals are wideband pulse signals with the bandwidth being 20Hz to 200kHz and the frequency range being within an audible sound or ultrasound frequency band range; 2) estimating a plurality of cascaded pre-filter time-domain responses used for carrying out the filtration treatment on the source signals on the basis of the iterative least square rule by combining the source signals and the focusing signals; and 3) re-sending the pre-filtered source signals by the guide sound source, and carrying out the operations of receiving, time-reversal and re-sending by the time-reversal array according to the conventional time-reversal process, so as to acquire the optimal focusing signal waveform at the location of the sound source. The invention can achieve the inverse-filtering and focusing effects within the time domains and recover the waveform of the source signals within the focusing region; the invention allows the random distribution of array elements and the difference in the frequency response among the array elements; and the invention has high spatial resolution.

Description

technical field [0001] The present invention relates to the field of time inversion acoustic focusing, in particular, the present invention particularly relates to an optimal active time defocusing method based on iterative least squares-prefiltering. Background technique [0002] The active time anti-focus method is widely used in the field of air, underwater and radio communication. In the high reverberation or uneven transmission medium, the active time anti-focus method can overcome the influence of multipath interference or unsteady propagation speed, and obtain reliable communication quality . [0003] The specific implementation of the conventional time-inverse process is as follows: [0004] Assume that the time-domain sequence vector of the source signal emitted by the pilot sound source is: [0005] s=[s(0)s(1)...s(N-1)] T [0006] Among them, N is the number of sampling points of the time-domain discrete sequence of the source signal. Assume that the Green's ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G10K11/26G10K11/32H03H21/00
Inventor 马登永杨军
Owner INST OF ACOUSTICS CHINESE ACAD OF SCI
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