CN1202407C - Method for identifying non-stationary acoustic source characteristics by bias coherent technology - Google Patents

Abstract

The present invention relates to a method for identifying non-stationary acoustic source characteristics by bias coherent technology, which belongs to the field of the noise class in the physics. The present invention is used for the occasion of the complex circulation stationary acoustic field of a plurality of acoustic sources, a smooth circulation theory replaces Fourier transformation, bias coherent analysis technology which is suitable for the circulation stationary acoustic field is put forward and is used for the separation of the part of the acoustic field of the circulation stationary acoustic field. The present invention comprises the method as follows: firstly the number and the position of a reference source are determined, the microphone array of the reference source is arranged, the signal of the reference source is extracted, then the microphone array is designed again to scan and measure a holographic surface and collect the data of the holographic surface; then the part of the acoustic field of each acoustic source is separated by means of the bias coherent analysis technology of the stationary circulation. The present invention can analyze the complex circulation stationary acoustic field which is formed by the a plurality of circulation stationary acoustic sources, and can obtain the part of the acoustic field which is respectively formed by each acoustic source, three-dimensional acoustic field distribution which is formed by each acoustic source can be calculated by the signals of acoustic pressure which is measured from a holographic plane, and the visualization of the propagation path of each acoustic source can be realized.

Description

Adopt the method for inclined to one side coherent technique identification non-stationary sound source characteristic

Technical field

What the present invention relates to is a kind of method of identifying sound source characteristic, and particularly a kind of method of utilizing the inclined to one side phase stem portion sound field separation technique identification non-stationary sound source characteristic of cyclo-stationary sound field belongs to the noise field in the physics class.

Background technology

Understanding to the noise source characteristic is the prerequisite of control noise, therefore, in order to control noise effectively, before noise reduction measure is implemented, must at first carry out the noise source diagnosis, determines each position, overriding noise seedbed, and characteristic.Along with the development of modern signal processing technology ground, spectral analysis technology, relevant and partial coherence analysis technology, sound intensity analytical technology and sound near-field holography technology etc. have obtained developing by leaps and bounds.Find by literature search, M.A.Tomlinson is at " Applied Acoustics " (57 (1999): write articles " Partial source discrimination innear field acoustic holography " (" applied acoustics " 243-261), part source identification in the near field acoustic holography), this article has proposed the part sound source isolation technics of near field acoustic holography partial coherence analysis, can diagnose noise source effectively.But these technology can only be analyzed steady sound field, therefore, are necessary to propose new technology, are used for the analysis of non-stationary sound field.Yet, for general non-stationary sound field, become when the statistical property parameter of acoustical signal is, thereby also replace ensemble average with regard to unrenewable time average, make data acquisition very difficult, be difficult to analyze the characteristic of sound field.

The cyclo-stationary signal is the special non-stationary signal of a class because the cyclic stationary of self uniqueness, make single acquisition to record have the cycle ergodic property, this specific character provides non-stationary signal to analyze possibility.The cyclo-stationary signal has crucial realistic meaning in engineering is used, for example rotating machinery is because the physical arrangement of symmetry or near symmetrical and periodic working motion pattern, its sound field has the obvious periodic time varying characteristic, and acoustical signal has cyclostationarity.In further retrieving, find as yet and the identical or similar bibliographical information of theme of the present invention.

Summary of the invention

The objective of the invention is to overcome deficiency of the prior art, a kind of method of identification non-stationary sound source characteristic is provided, achieve and obtain the part sound field that each sound source forms respectively, near-field holography by the cyclo-stationary sound field is rebuild, can also obtain three-dimensional sound field by the measurement data on the plane and distribute, realize that each sound source route of transmission is visual.

The present invention is achieved by the following technical solutions, the present invention is in the occasion of the steady sound field of complex loops of a plurality of sound sources generations, adopt the theoretical alternative traditional Fourier transform of cyclo-stationary, proposition is applicable to the partial coherence analysis technology of cyclo-stationary sound field, and it part sound field that is used for the cyclo-stationary sound field separated, at first determine the quantity and the position of reference source, and layout reference source microphone array, extract reference source signal, design microphone array again holographic facet is carried out scanning survey, gather the holographic facet data, then, utilize circulation partial coherence analysis technology, separate the part sound field of each sound source, obtain the relevant Density Distribution of spectrum of part sound field.

Below the inventive method is done further to limit, method step is as follows:

1, determines the quantity and the position of reference source, and arrange and extract reference source signal by the reference source microphone array.For this reason, need to determine the number K and the position of reference source, can adopt the near field compbined test analysis (or claiming inclined to one side odd value analysis) of steady sound field to obtain.

2, arrange holographic facet measuring microphone array,, can on whole hologram plane, arrange microphone if port number is abundant; If port number is not enough, microphone can be arranged to linear array, measure in the enterprising line scanning of whole holographic facet; In the holographic facet data acquisition, utilize the reference source array to gather the reference source acoustical signal.During measurement, the acoustical signal of the whole microphone passages of synchronous acquisition, recording storage are in computing machine, magnetic tape recorder or other equipment, and establishing the holographic facet port number is Q.

3, analyze the acoustical signal of being gathered, choose the frequency and the cycle frequency that can reflect sound field characteristic, can analyze the spectral density function of each reference source signal and select.

4, utilize the holographic facet time domain acoustical signal data collect and the time domain acoustical signal data of reference source, calculate the circulation of the reference source signal on selected frequency f and the cycle frequency α and compose relevant density matrix (S _Rr ^α(f)) _{K * K}, and the relevant density matrix (S of circulation cross-spectrum of microphone signal on reference source signal and the holographic facet _Rp ^α(x, y, z _h, f)) _{K * Q}And (S _Pr ^α(x, y, z _h, f)) _{Q * K}Can be by these three the relevant density matrix of circulation spectrum, the circulation that obtains acoustical signal on the holographic facet is from the relevant density matrix (S of spectrum _Pp ^α(x, y, z _h, f)) _{Q * 1}, computing method are suc as formula (1):

${\left(S_{\mathrm{pp}}^{\mathrm{\α}}\left(f\right)\right)}_{Q\×1}=\mathrm{diag}\left({\left(S_{\mathrm{pr}}^{\mathrm{\α}}\left(f\right)\right)}_{Q\×K}\mathrm{inv}\left({\left(S_{\mathrm{rr}}^{\mathrm{\α}}\left(f\right)\right)}_{K\×K}\right){\left(S_{\mathrm{rp}}^{\mathrm{\α}}\left(f\right)\right)}_{K\×Q}\right)------\left(1\right)$

Wherein, the diagonal element of matrix is extracted in diag () expression, and inv () represents that this relational expression is set up to matrix inversion in whole sound field, this formula has reflected the time phase relation of reference source and holographic facet information, can be used to scanning collection to holographic facet acoustic pressure information carry out phase-locking.

5, utilize holographic facet data and the reference source data that collect, the partial coherence analysis that circulates separates the part sound field that obtains each sound source, and method is as follows:

Set mark r and represent r reference source signal, the signal of measuring point p on the hologram plane that subscript p represents to measure, then after the influence of removing r-1 reference source, r reference source in the relevant density of spectrum of the output signal of holographic facet measuring point place generation is:

$S_{p:r\·(r-1)!}^{\mathrm{\α}}\left(f\right)={{\mathrm{\γ}}_{\mathrm{rp}\·(r-1)!}^{\mathrm{\α}}}^2\left(f\right)S_{\mathrm{pp}\·(r-1)!}^{\mathrm{\α}}\left(f\right)------\left(2\right)$

Wherein:

${{\mathrm{\γ}}_{\mathrm{rp}\·(r-1)!}^{\mathrm{\α}}}^2\left(f\right)=\frac{S_{\mathrm{rp}\·(r-1)!}^{\mathrm{\α}}\left(f\right)S_{\mathrm{pr}\·(r-1)!}^{\mathrm{\α}}\left(f\right)}{S_{\mathrm{rr}\·(r-1)!}^{\mathrm{\α}}\left(f\right)S_{\mathrm{pp}\·(r-1)!}^{\mathrm{\α}}\left(f\right)}$ Be the inclined to one side coherence function that circulates.

The present invention has substantive distinguishing features and marked improvement, the present invention utilizes the periodicity of the uniqueness of cyclo-stationary sound field, on the basis of partial coherence analysis technology, circulation partial coherence analysis technology has been proposed, and on the basis of the inclined to one side coherent technique harmony near-field holography technology of circulation, invented circulation partial coherence analysis part sound field separation technique, can analyze, obtained the part sound field that each sound source forms respectively the steady sound field of complex loops that a plurality of cyclo-stationary sound sources form; Near-field holography by the cyclo-stationary sound field is rebuild, and can also extrapolate the three-dimensional sound field distribution that single sound source forms the sound pressure signal that records on hologram plane, realizes that each sound source route of transmission is visual.

Embodiment

Provide following examples in conjunction with the inventive method content:

1, supposes known sound source number and position, adopt two loudspeaker sounding to form two cyclo-stationary sound sources, arrange two microphones, extract reference source signal.

The driving source of loudspeaker is:

Vsourcel＝Acos(2πf ₁t)*noise(t)

Vsource2＝B(1+Ccos(2πf _bt))*cos(2πf _at)

Wherein, A=10, B=C=1, f1=300, f _a=300, f _b=120, noise is connected with coloured noise for band.

2,25 microphones are arranged to linear array, measure, form 25 * 25 holographic facet array in the enterprising line scanning of whole holographic facet; In the holographic facet data acquisition, utilize two reference source microphones to gather the reference source acoustical signal.During measurement, the acoustical signal of the whole microphone passages of synchronous acquisition, recording storage is in computing machine or other equipment.

3, analyze the acoustical signal of being gathered in the laboratory playback, choose the frequency f=120Hz and the cycle frequency alpha=600Hz that can reflect sound field characteristic.

4, utilize holographic facet data and the reference source data collect, the circulation of analyzing the reference source signal on selected frequency f and the cycle frequency α is from composing relevant density matrix (S _Rr ^α(f)) _{K * K}, the relevant density matrix (S of circulation cross-spectrum of reference source signal and holographic facet upper sensor signal _Rp ^α(x, y, z _h, f)) _{K * Q}And (S _Pr ^α(x, y, z _h, f)) _{Q * K}

5, separate the part sound field that obtains each sound source.

6, utilize the near-field holography reconstruction formula of cyclo-stationary sound field to carry out sound field rebuilding, to obtain the three-dimensional information of each sound source part sound field.

Find when two reference source signal coherences that obtain are smaller in this embodiment, separating effect is very good, can analyze significantly and obtain two sound sources sound field separately, when two reference source signal coherences that obtain are very strong, separating effect is still very good, and the inherent coherence that can weaken to a great extent when adopting circulation partial coherence analysis separating part sound field between the reference source array is described.

Claims (4)

1, a kind of method of identification non-stationary sound source characteristic, it is characterized in that the occasion of the steady sound field of complex loops that produces in a plurality of sound sources is at first determined the quantity and the position of reference source, and layout reference source microphone array, extract reference source signal, design microphone array again holographic facet is carried out scanning survey, gather the holographic facet data, then, utilize cyclo-stationary partial coherence analysis technology, separate the part sound field of each sound source, obtain the relevant Density Distribution of spectrum of part sound field.

2, the method for identification non-stationary sound source characteristic according to claim 1 is characterized in that, below the present invention is made further qualification, and concrete method step is as follows:

(1) adopts the near field compbined test analysis of steady sound field or claim quantity and the position that inclined to one side odd value analysis is determined reference source, and arrange and extract reference source signal by the reference source microphone array;

(2) arrange holographic facet measuring microphone array, this array can be plane or curved array, perhaps use the linear array scanning survey, in the holographic facet data acquisition, utilize the reference source array to gather the reference source acoustical signal, during measurement, the acoustical signal of the whole microphone passages of synchronous acquisition, recording storage is in registering instrument or computing machine, and establishing the holographic facet port number is Q;

(3) analyze the acoustical signal of being gathered, choose the frequency and the cycle frequency of reflection sound field characteristic by the spectral density function of analyzing each reference source signal;

(4) utilize the holographic facet time domain acoustical signal data collect and the time domain acoustical signal data of reference source, calculate selected frequency f and compose relevant density matrix with the reference source signal circulation on the cycle frequency α ${\left(S_{\mathrm{rr}}^{\mathrm{\α}}\left(f\right)\right)}_{K\×K},$ And the relevant density matrix of circulation cross-spectrum of microphone signal on reference source signal and the holographic facet ${\left(S_{\mathrm{rp}}^{\mathrm{\α}}(x,y,z_h,f)\right)}_{K\×Q}$ And ${\left(S_{\mathrm{pr}}^{\mathrm{\α}}(x,y,z_h,f)\right)}_{Q\×K},$ Can be by these three the relevant density matrix of circulation spectrum, the circulation that obtains acoustical signal on the holographic facet is from the relevant density matrix of spectrum ${\left(S_{\mathrm{pp}}^{\mathrm{\α}}(x,y,z_h,f)\right)}_{Q\×1},$ Computing method are as follows:

${\left(S_{\mathrm{pp}}^{\mathrm{\α}}\left(f\right)\right)}_{Q\×1}=\mathrm{diag}\left({\left(S_{\mathrm{pr}}^{\mathrm{\α}}\left(f\right)\right)}_{Q\×K}\mathrm{inv}\left({\left(S_{\mathrm{rr}}^{\mathrm{\α}}\left(f\right)\right)}_{K\×K}\right){\left(S_{\mathrm{rp}}^{\mathrm{\α}}\left(f\right)\right)}_{K\×Q}\right)$

3, the method for identification non-stationary sound source characteristic according to claim 2 is characterized in that, in the step (4), utilizes the holographic facet data and the reference source data that collect, and the partial coherence analysis that circulates separates the part sound field that obtains each sound source, and method is as follows:

If S represents the spectral density function that circulates, subscript r represents r reference source signal, the signal of measuring point p on the hologram plane that subscript p represents to measure, subscript α represents cycle frequency, f represents the frequency of acoustical signal, the same meaning of symbol in subscript ": " and " " and the common inclined to one side coherence function, wherein ": " represents the coherent relationships between two signals, r-1 is removed in following target mid point " r (r-1) " expression from r influence, then after the influence of removing r-1 reference source, r reference source computing, the relevant density of circulation spectrum of the output signal that produces at holographic facet measuring point place is:

$S_{p:r\·(r-1)!}^{\mathrm{\α}}\left(f\right)={{\mathrm{\γ}}_{\mathrm{rp}\·(r-1)!}^{\mathrm{\α}}}^2\left(f\right)S_{\mathrm{pp}\·(r-1)!}^{\mathrm{\α}}\left(f\right)$

Wherein:

${{\mathrm{\γ}}_{\mathrm{rp}\·(r-1)!}^{\mathrm{\α}}}^2\left(f\right)=\frac{S_{\mathrm{rp}\·(r-1)!}^{\mathrm{\α}}\left(f\right)S_{\mathrm{pr}\·(r-1)!}^{\mathrm{\α}}\left(f\right)}{S_{\mathrm{rr}\·(r-1)!}^{\mathrm{\α}}\left(f\right)S_{\mathrm{pp}\·(r-1)!}^{\mathrm{\α}}\left(f\right)}$ Be the inclined to one side coherence function that circulates.

4, the method for identification non-stationary sound source characteristic according to claim 1 and 2, it is characterized in that, near-field holography by the cyclo-stationary sound field is rebuild, and obtains the three-dimensional sound field distribution that single sound source forms the sound pressure signal that records on hologram plane, realizes that each sound source route of transmission is visual.