scholarly journals Binaural Heterophasic Superdirective Beamforming

Sensors ◽  
2020 ◽  
Vol 21 (1) ◽  
pp. 74
Author(s):  
Yuzhu Wang ◽  
Jingdong Chen ◽  
Jacob Benesty ◽  
Jilu Jin ◽  
Gongping Huang

The superdirective beamformer, while attractive for processing broadband acoustic signals, often suffers from the problem of white noise amplification. So, its application requires well-designed acoustic arrays with sensors of extremely low self-noise level, which is difficult if not impossible to attain. In this paper, a new binaural superdirective beamformer is proposed, which is divided into two sub-beamformers. Based on studies and facts in psychoacoustics, these two filters are designed in such a way that they are orthogonal to each other to make the white noise components in the binaural beamforming outputs incoherent while maximizing the output interaural coherence of the diffuse noise, which is important for the brain to localize the sound source of interest. As a result, the signal of interest in the binaural superdirective beamformer’s outputs is in phase but the white noise components in the outputs are random phase, so the human auditory system can better separate the acoustic signal of interest from white noise by listening to the outputs of the proposed approach. Experimental results show that the derived binaural superdirective beamformer is superior to its conventional monaural counterpart.

1993 ◽  
Vol 10 (4) ◽  
pp. 503-508 ◽  
Author(s):  
Robert O. Gjerdingen

If one hypothesizes rhythmic perception as a process employing oscillatory circuits in the brain that entrain to low-frequency periodicities in the neural firings evoked by an acoustic signal, then among the conceptually purest probes of those oscillatory circuits would be acoustic signals with only simple sinusoidal periodicities in the appropriate frequency range (perhaps from 0.3 Hz to 20 Hz). Such signals can be produced by the low- frequency amplitude modulation of an audible carrier wave by one or more sinusoids. The resulting rhythms are "smooth" in that their amplitude envelopes are smoothly varying with no obvious points of onset or offset. Because preliminary experiments with smooth rhythms have produced some unexpected results, and because smooth rhythms can be precisely controlled and varied (including, for example, the digital filtering of their Fourier components in the frequency domain), they are proposed as versatile stimuli for studies in rhythmic perception.


2016 ◽  
Vol 113 (29) ◽  
pp. 8308-8313 ◽  
Author(s):  
Eyal Wigderson ◽  
Israel Nelken ◽  
Yosef Yarom

Discriminating external from self-produced sensory inputs is a major challenge for brains. In the auditory system, sound localization must account for movements of the head and ears, a computation likely to involve multimodal integration. Principal neurons (PNs) of the dorsal cochlear nucleus (DCN) are known to be spatially selective and to receive multimodal sensory information. We studied the responses of PNs to body rotation with or without sound stimulation, as well as to sound source rotation with stationary body. We demonstrated that PNs are sensitive to head direction, and, in the presence of sound, they differentiate between body and sound source movement. Thus, the output of the DCN provides the brain with enough information to disambiguate the movement of a sound source from an acoustically identical relative movement produced by motion of the animal.


1961 ◽  
Vol 38 (3) ◽  
pp. 545-558 ◽  
Author(s):  
NOBUO SUGA ◽  
YASUJI KATSUKI

1. The impulses from the tympanic organ are transmitted at the prothoracic ganglion to a central neuron, the auditory T large fibre, which lies in the cord between the brain and the metathoracic ganglion. The impulses in the T large fibre are conducted rostrally and caudally with the same discharge pattern. Information is sent up to the brain, and down to the metathoracic ganglion, after a delay of about 12 msec. 2. The impulses from the cercal hair sensilla are transmitted to two similar auditory C large fibres which lie in the cord between the metathoracic and last (6th) abdominal ganglia and are then sent up to the mesothoracic ganglia by other auditory large fibres. 3. Central inhibitory interaction between the impulses from the tympanic nerves of the two sides are shown by a marked increase of impulses in the T large fibre following section of one of the tympanic nerves. No inhibitory interaction is found between the impulses from the two cercal nerves. 4. The auditory T large fibre receives not only the excitatory effect from the ipsilateral tympanic nerve at the prothoracic ganglion, but also the inhibitory and weak excitatory effects from the contralateral one. 5. The response range of the T large fibre is narrower than the threshold curve of the tympanic nerve and corresponds with one type of response range in the tympanic neurons. The response ranges of the C large fibres correspond closely with the threshold curve of the cercal nerve. 6. A large difference in threshold between the two T large fibres is found in the response to sound incident from the side. The number of impulses in the T large fibre nearer to the sound source is greater than in that farther from the source. 7. The difference in the number of impulses between the two T large fibres is most marked in the response to sound of the frequency which is dominant in stridulation. This difference is due to the mutual inhibitory interaction of neurons which modifies the number of impulses without changing the threshold of the tympanic large fibre. 8. It is suggested that the central inhibitory interaction increases the information about a sound source and plays an important role in the mechanism of the directional sense. 9. The stridulation of the group activates the tympanic nerve and evokes synchronized discharge in the T large fibre, but scarcely at all in the primary C large fibre. The tympanic organ and its neural network seem well adapted to reception of stridulation. 10. It is concluded that though neither of the two sound receptive organs--the tympanic organ and the cercal hair sensilla--can perform frequency analysis, the insect may be able to do so by making use of both organs, since they have different frequency ranges and are served by different auditory large-fibre tracts.


2021 ◽  
Author(s):  
Yunjie Shi ◽  
Mengke Yin ◽  
Zijue Zhu ◽  
Shun Wang ◽  
Panting Niu ◽  
...  

Abstract In the research field of fiber-optic hydrophone, the performance of demodulation scheme is crucial. In this work, a phase-generated-carrier (PGC) demodulation scheme based on high-frequency sound source is proposed. Highfrequency acoustic signal from the external sound source is applied to the fiber-optic hydrophone to achieve phase modulation of the interference signal instead of the piezo-electrical transducer (PZT) or frequency-modulated laser. It possesses the merits of low system complexity and low cost. Through the acoustic detection experiment, we achieve demodulation of acoustic signal at frequency varying from 300 Hz to 800 Hz, and the signal-to-noise ratio (SNR) is higher than 45 dB. Furthermore, the proposed scheme is successfully applied to time division multiplexing (TDM) experiment.


2020 ◽  
Vol 15 (5) ◽  
pp. 729-737
Author(s):  
Gong Chen ◽  
Lei Cai ◽  
Lv Zong ◽  
Yan Wang ◽  
Xin Yuan

Passive acoustic technology (PAT) is an important tool to acquire the passive acoustic signals from marine organisms. In this paper, PAT fish detection is introduced at great length, including the relevant instruments, signal processing methods, and workflow. Focusing on the key tasks of PAT fish detection, the authors proposed a sparse decomposition algorithm that extracts coherent ratio of passive fish acoustic signal, and designed a feature extraction method for that signal based on speech imitation technology. Experimental results demonstrate that the proposed sparse decomposition algorithm can detect fish acoustic signal accurately at low signal-to-noise ratios (SNRs), and the proposed feature extraction method can effectively extract fish acoustic signals from the marine background. The research results shed important new light on the protection and management of fishery resources in the seas and oceans.


2016 ◽  
Vol 16 (6) ◽  
pp. 220-231
Author(s):  
Hong Kun Wang ◽  
Shou Xiang Wang ◽  
Jing Nie

Abstract With the formation of China’s large power grid, the security of the network is particularly important. The contaminant flashover of insulators has a serious impact on the operation safety of a high voltage power network. In this paper, the acoustic signals’ characteristics of the contaminant insulators flashover are analyzed, and, as a result, the correlation between the acoustic signal and the contaminant insulator flashover is established. To experiment with contaminant insulator for three different Equivalent Salt Deposit Densities (ESDD), acoustic signals were collected separately. Then, the contaminant insulators’ acoustic signals of flashover were analyzed by wavelet packet. The characteristics of the signals were obtained, and they can be judged for contaminant flashover warning.


Author(s):  
Таtiana М. Tkachenko ◽  
Yulia H. Pilkevich ◽  
Heorhii M. Rozorinov

The basic sources of contamination and obstruction of reservoirs are cleared not enough sewer water of industrial and communal enterprises, large stock-raising complexes, wastes of production; upcast of water and railway transport; wastes of roughing-out of flax, pesticides and other. Сontaminents, getting in natural reservoirs, result in the quality changes of water, that, mainly, appear in the change of physical properties of water, in the change of chemical composition of water, in a presence floating substances on the surface of water and laying of them on the bottom of reservoirs. The increases of population, expansion of old and origin of new cities considerably increased entering of domestic flows internal reservoirs. Synthetic cleansers that is widely used in the way of life contaminate reservoirs in a yet greater degree. In the total the capacity of waters goes down for oxigenating, activity of bacteria that mineralize organic substances is paralysed. The unfavorable ecological state of many freshwater ecosystems inflicts substantial harm to the fish resources of reservoirs and puts under a threat possibility not only to develop fish industry, conducting fish artificially, but also simply to catch her. All of it stimulate to do events in relation to the improvement of the ecological state of fresh reservoirs. Voice vibrations are the important constituent of the ecological monitoring of the biota state of fresh reservoirs. Information is about formation of sound in a reservoir part of that is activity of fishes turns out by means of acoustic sensors, that farther yields to computer treatment. The modern methods of recognition of fish acoustic patterns are based on the standards of signals, with properties of average estimations, or on comparisons of acoustic signals with a standard. It is shown that for creation of standards, as a rule, executed: previous signal processing, extraction of features of acoustic signal. Acoustic signals that act from movable objects – fishes can change depending on objective external terms and physical state of reservoirs. The hard algorithms of recognition of acoustic patterns are characterized high probability of error. In this connection repressing are adaptive algorithms of recognition of acoustic patterns. In the process of forming of standards clarification of software comes true according to the features of acoustic signal. Realization of process of creation of standards allows to determine the measure of functional readiness of parameters and knowledge base for the decision of recognition tasks of acoustic signals. In the process of recognition the probability terms of the correct comparing are set to the standard, on default of that an algorithm stops to be executed and requires additional studies. It requires creation of standards that reflect the characteristic features of fish signals. Presently for authentication mostly choose such pattern of acoustic signals, as period length of signal fundamental wave. It can be determined or by the search of maximal value in an autocorrelation function, or by the search of minimum value in the function of mean value of difference of signal amplitudes, or by the search of difference of two maximal values in the sequence of going into detail wavelet-coefficients. It is shown that for the tasks of recognition of fish acoustic patterns, most exact and requiring the least studies there is presentation of acoustic signal as a set of sign vectors of frames. In detail methodologies of the period selection of fundamental wave of acoustic signal were analysed: SIFT, EFT-А and EFT-WT. Methodology of EFT-WT is characterized absence of the thresholds set in good time; by the rapid search of period of fundamental wave; by absence of dependence on a noise-level, as a certain range of frequencies is investigated. At the same time calculable complication of wavelet transform is relatively high, in this connection it is necessary optimization of calculation algorithms.


2019 ◽  
Vol 8 (3) ◽  
pp. 2012-2016

This paper presents a novel technique for calculation of attenuation of acoustic signals in the materials in underwater channel. A laboratory procedure and algorithms have been developed for finding attenuation. In many applications like sonar signal processing acoustic signal attenuation in the dome or in an enclosure are required to be known. Finding the actual attenuation while signal passes through the materials is very useful in calculating the precise power transmitted through the enclosures. The attenuation in materials mainly dependent on type of material, signal frequency and launch angle of the signal. A proper procedure has been presented in this paper


2022 ◽  
Author(s):  
Wei-Wei Kan ◽  
Qiu-Yu Li ◽  
Lei Pan

Abstract The scattering behavior of the anisotropic acoustic medium is analyzed to reveal the possibility of routing acoustic signals through the anisotropic layers with no backscattering loss. The sound-transparent effect of such medium is achieved by independently modulating the anisotropic effective acoustic parameters in a specific order, and experimentally observed in a bending waveguide by arranging the subwavelength structures in the bending part according to transformation acoustics. With the properly designed filling structures, the original distorted acoustic field in the bending waveguide is restored as if the wave travels along a straight path. The transmitted acoustic signal is maintained nearly the same as the incident modulated Gaussian pulse. The proposed schemes and the supporting results could be instructive for further acoustic manipulations such as wave steering, cloaking and beam splitting.


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