Acoustic Output Signal Research Articles

Sound response of baker’s yeast and aqueous solutions to external influences investigated by interferometry

Application of a fiber Fabry–Perot interferometer for studying the sound response of cellular structures and aqueous solutions is discussed. Aqueous suspensions of baker’s yeast and commercial natural drinking water, treated by electrolysis, were applied as models in order to mimic processes in biological tissues and liquids. The distribution of frequency intensities in the acoustic spectrograms yields evaluation of a biological system response to the external exposure. In a yeast suspension, few minutes after the sound irradiation with the frequency of 3 kHz and the sound pressure of 50 to 60 dB, we observed regular fluctuations in the output acoustic signal, with the maximal period of about 100 s. Furthermore, a sound response in the frequency range of 400 to 600 Hz maintained in signals for few minutes after the exposure. The observed results demonstrate that the proposed interferometric sensor has strong potential in biology and medicine since it is quite simple, portable, and highly sensitive device for analyses the sound response of a living system.

Mine acoustic wave signal generator

Based on the requirement of mine acoustic wave technology for the signal generator, this paper aims to explore the key factors affecting the amplitude of the output acoustic signal of rare earth giant magnetostrictive materials (RE-GMM), including bar size, magnetic field strength and pre-stress in order to set an optimal plan based on the influence of various factors on output signal amplitude. This paper establishes a test platform for measuring the output performance of the acoustic signal generator and to test the prototype. Result verifies the correctness of the scheme.

The Safety of Diagnostic Ultrasound in Ophthalmology

The literature review presents information about ultrasound use in diagnosis, therapeutic and surgical treatment of eye diseases. Due to experimental studies it was proved that ultrasound of different power, intensity and exposure causes thermal, mechanical and biological effect on the eye tissue. Thermal effect caused by ultrasonic energy absorption by biological tissues, which is converted from acoustic energy into thermal energy. The mechanical effect is determined by the amplitude of ultrasonic pressure acting on the eye structures during the examination. For the safety of ultrasound scanning, such concepts as thermal (TI) and mechanical (MI) indices have been introduced, which allows to control the level of acoustic impact on tissues. Ultrasound diagnosis in ophthalmology went a long way from one-dimensional echography (A-mode) to the complex scanning in real time, which allows to visualize different structural elements of the eye. Ultrasound eye examination is non-invasive and highly informative and thereby one of the main instrumental diagnosis methods in ophthalmology. Combination of images in gray scale, highly sensitive color and energy Doppler, 3D and sonoelastography to date greatly increased the diagnostic capabilities of ultrasound for simultaneous qualitative and quantitative assessment the eye and orbit in normal and pathological conditions. Therefore general ultrasonic diagnostic systems are widely used in clinical practice, with obligatory correction of TI and MI values. Recommendations of the international professional organizations such as Food and Drug Adminisration (FDA) and American Institute of Ultrasound in Medicine (AIUM))are widely used for the ultrasonic examination of eye pathology, according to which the lowest levels of exposure and intensity of the output acoustic signal (TI and MI) should be set to get a high-quality image. There are still a lot of clinical and experimental studies to determine the optimal modes of ultrasound eye and orbit examination. However, the safety of ultrasound and its effect on eye structures are still need to be studied.

Systematic analysis of fluid-structure-acoustic interactions in an ex-vivo porcine phonation model

Background: The phonation process is a complex interaction of different components, namely, the airflow from the lungs, the mucosal tissue in the larynx, and the resulting acoustic signal. From clinical experience, it is assumed that the presence of a pre-phonatory gap, oscillation asymmetries, and aperiodicities constitute detrimental factors to the resulting voice quality. In order to gain an in-depth understanding of the cause-effect chain and enable effective therapeutic measures, the crucial elements of the process need to be studied in isolation. Materials & Methods: The presented experimental set-up allows a systematic control and monitoring of the individual components of the excised porcine larynx. Varying degrees of asymmetric adduction, pre-phonatory gap size and flow rate reproduce irregular oscillation patterns associated with pathologic voice production. Results: The statistical analysis based on k-means clustering allows the identification of structural and aero-dynamic factors which influence voice quality. In addition to an increase in glottal closure and oscillation symmetry, an increase in glottal flow resistance produced a beneficial effect on the acoustic output signal and the closely coupled subglottal pressure. Conclusion: The clinical applicability and therapeutic value of these insights must be assessed in further studies.

Applications of acoustic radiation force for material characterization and imaging

Acoustic radiation force has been used in many interesting medical and industrial applications in the past two decades. The fact that radiation stress can be confined to a small focal area and exerted remotely inside or on an object allows one to use this phenomenon in a variety of ways to explore properties of the object. Vibro-acoustography is a material characterization and imaging method that uses harmonic or impulsive acoustic radiation force to stimulate the targeted material and receives the resulting acoustic response. The output acoustic signal is then used to extract important information about the object. Biomedical applications of vibro-acoustography and its closely related methods include imaging, flow detection, and tissue characterization. Other applications include non-destructive evaluation/testing of materials, modal analysis of small structures, and microscopy. This talk presents an overview of vibro-acoustography and its closely related techniques over the past 20 years. Various biomedical and industrial applications will be presented. The talk will conclude with a discussion on potential future applications of this technology.

Relationship between acoustic cavitation bubble behavior and output signal from tough hydrophone using high-speed camera in high-frequency and low-frequency acoustic fields

In previous works, our developed tough hydrophone was resistant to high-pressure fields (15 MPa). During the experiment, acoustic cavitation bubbles were generated around the tough hydrophone tip, because the tip was slightly larger than the wavelength and was flat. In this study, the influence of the tough hydrophone on high-intensity 1 MHz and 22 kHz acoustic fields was investigated by visualizing bubbles around the hydrophone and recording the waveform from the hydrophone at the same time. As a result, the hydrophone with a flat tip can be used for measurements in 1 MHz and 22 kHz high-intensity acoustic fields under certain conditions where acoustic bubble cloud generation on the hydrophone tip is avoided. The change in output waveforms from the hydrophone was negligibly small, even when collision and sticking of the acoustic bubble to the hydrophone tip occurred.

Построение наземной сети для прогнозирования оползневых процессов с высокой достоверностью

Landslides are the geological event, which lead to huge losses yearly in the scale of whole planet. Landslides are the spatial dynamic process and can develop during the long time period. Because that all control point type measurements in the field should be carried out at the sufficiently large area. At the present time the empirical GIS based models of landslides allow to estimate the potential of landslide occurrence. At the same time there are the technologies of wireless networks realized as technical systems making it possible to found and predict the landslides. Such systems are composed of distributed on area colons of tenzometric sensors with acoustic output signal and generator of start radio signal. The necessary condition for utilization of these signals is presence in them of identification signatures which leads to complication of technical system and increase the background noise level. The suggested alternative variant for development of prediction system make it possible not to form and emit the big numberof radio signals with identification signatures which promote for decrease the level of background noise signal.

APPARATUS, METHOD AND COMPUTER PROGRAM

An apparatus, method and computer program, the apparatus comprising: including a loudspeaker configured to convert an electrical input signal into an acoustic output signal; a connecting portion configured to interchangeably connect to either a first adapter or a second adapter where the first adapter is configured to fit in a user's ear canal and the second adapter is configured to fit to a user's concha; and a regulator for regulating sound pressure level created by the acoustic output signal at an ear drum of the user in dependence on whether the first adapter or the second adapter is connected to the connecting portion.

APPARATUS, METHOD AND COMPUTER PROGRAM FOR PROVIDING AN ACOUSTIC OUTPUT SIGNAL USING AN EARPIECE

An apparatus, method and computer program, the apparatus including a loudspeaker configured to convert an electrical input signal into an acoustic output signal; a connecting portion configured to interchangeably connect to either a first adapter or a second adapter where the first adapter is configured to fit in a user's ear canal and the second adapter is configured to fit to a user's concha; and a regulator for regulating sound pressure level created by the acoustic output signal at an ear drum of the user in dependence on whether the first adapter or the second adapter is connected to the connecting portion.

METHOD AND APPARATUS FOR MONITORING A HEARING AID

A hearing aid contains a microphone detecting an acoustic input signal and converts it to an electrical output signal, a receiver producing an acoustic output signal being dependent on an electrical output signal of the microphone, and a transmitter transmitting a monitoring signal, which is dependent on the electrical output signal. A transceiver contains a receiver for receiving the monitoring signal, and a signal processing device for processing the monitoring signal. The signal processing device processes the monitoring signal to produce an indication signal which is acoustically restricted with respect to the monitoring signal such that it simulates a restricted hearing capability of a person, or which indicates an operating/signal state of the hearing aid. The transmission of the monitoring signal to the transceiver and the processing to form the indication signal provides information about the state of the hearing aid for monitoring of the hearing aid.

HEARING AID WITH FEEDBACK MODEL GAIN ESTIMATION

A hearing aid 100 comprises an input transducer 10 for transforming an acoustic input signal into an electrical input signal 15, a processor 20 for generating an elec~tricaloutput signal by amplifying the electrical input signal with a processor gain, an output transducer 30 for transforming the electrical output signal into an acoustic output signal, an adaptive feedback suppression filter 40 for generating a feedback cancellation signal by using an error signal generated from the difference between the feedback cancellation signal and the electrical input signal, and a model gain estimator 60 generating an upper processor gain limit by determining the gain in the adaptive feedback suppression filter.

DYNAMIC DISTORTION ELIMINATION FOR OUTPUT AUDIO

A method ( 200 ) for improving quality of output audio ( 126 ). The method can include detecting an output acoustic signal ( 128 ) and generating a receive audio signal ( 134 ) based, at least in part, on the detected output acoustic signal. A frequency domain representation ( 140 ) of the receive audio signal can be compared to a frequency domain representation ( 138 ) of a source audio signal ( 124 ) from which the output acoustic signal is generated. At least one distortion signal ( 142 ) in the receive audio signal can be identified, and the source audio signal can be selectively equalized to reduce an amplitude of the source audio signal at a frequency that correlates to the distortion signal.

DOOR WITH STRUCTURAL COMPONENTS CONFIGURED TO RADIATE ACOUSTIC ENERGY

A door leaf includes a stiff, light structural part that maintains fed-in vibrational energy and, by flexural waves, propagates this energy in at least one active surface perpendicular to its thickness to distribute resonance mode vibration components over at least one surface, which has specified, preferred locations or sites within it for transducer devices, which are affixed on the structural part at one of the locations or sites to set the structural part into vibration and to allow it to resonate, thus creating an acoustic radiator that delivers an acoustic output signal when it vibrates in resonance, the front and/or the rear cover panel of the door leaf being part of the stiff, light structural component. The transducer(s) is/are situated between the cover panels. This arrangement provides a door with a loudspeaker function, which needs no extra volume compared to an ordinary door, and which is able to provide sound reliably and comprehensively to one or more rooms, which adjoin this door acting as a loudspeaker. Advantageously, additional loudspeakers or loudspeaker boxes are not required in a room that receives sound by this door with loudspeakers.

ACOUSTIC SIGNAL PROCESSING APPARATUS AND ACOUSTIC SIGNAL PROCESSING METHOD

An apparatus for performing processing of an input acoustic signal to be reproduced by a loudspeaker, which generates a harmonic of a low pitch sound component equal to or lower than a predetermined low cutoff frequency, and generates a harmonic synthesized acoustic signal synthesizing the input signal with the harmonic. The apparatus generates an output acoustic signal which cuts off, from the harmonic synthesized acoustic signal, a low pitch sound component equal to or lower than the low cutoff frequency and a high pitch sound component equal to or higher than the high cutoff frequency. The apparatus sets a low and high cutoff frequencies in accordance with an output characteristic of a loudspeaker.

Hearing Aid Apparatus

There is described a hearing aid comprising input transducer means for converting input acoustic signals into electrical input signals, signal processor means and output transducer means. The signal processor means is operable to divide said electrical input signals into a plurality of frequency bands and to perform a contrast enhancement operation in each said frequency band, to increase the difference between the amplitudes of those frequency components of the input electrical signals having a relatively high amplitude and those frequency components thereof having a relatively low amplitude to produce output electrical signals in each said respective frequency band. The output transducer means is operable to produce an output acoustic signal corresponding to a combination of said output electrical signals.

Blind estimator for time delays in multipath acoustic channel estimator performance vs. noise and number of multipath

A Modified Blind Estimator (Modified Autocorrelation-based Estimator – MAE) algorithm is presented for estimation of time delays in multipath acoustic channel in the presence of uncorrelated noise. Here, the multipath acoustic channel output signal is modelled as a superposition of the delayed, attenuated and filtered versions of the stationary Gaussian stochastic input signal. Different performance measures have been introduced to characterise the performance of the estimator. The simulation results show that MAE performance approaches the equivalent Cramer-Rao Lower Bound (CRLB) in terms of Accuracy Percentage (AP) measures, AP CRLB , in the high Signal to Noise Ratio (SNR) ranges. Furthermore, it is observed from simulations that when the SNR increases or the number of paths decreases the performance of MAE improves.

Audio Watermarking Based on PCM Technique

igital instruments come to be used in Desk Top Music (DTM), live performance, etc. These performances are recorded as digital contents, and circulated actively through network and electronic media. Digital Water mark technology paid much attention to solve the problem of illegal distribution & duplication when the digital contents are spread over electronic media. In this paper, we focus on a sound synthesized process in digital instruments, and propose a audio watermarking based on wavetable switching method. Certain watermarks are embedded in wavetables that are included in our digital instruments, and the insertion of secret messages is actualized with wavetable switching. Additionally, embedded watermarks can be extracted from the acoustic signal. The proposed method is able to achieve a real-time watermark, i.e., both musical performance and the insertion of watermark can be actualized. In this study, we focused on digital instrument to solve this problem. Digital instrument (like electronic piano, electric drum and so on) has been used for musical performances in practice, and digital instrument has a characteristic structure in its sound synthesis process. Additionally it was considered that characteristics of the synthesis could be used for real-time watermarking. The purpose of this study is to achieve a real-time watermarking technology with another approach for musical performance with digital instruments. In the proposed method, watermarks are embedded in the wavetable of digital instruments, and embedded data are extracted from the playback acoustic signal of digital instrument. Therefore, watermarks can be embedded in the output acoustic signal that is synthesized from the wavetable in real-time musical performance, and it can be useful for the copyrights protection of real-time generated acoustic media.

An electroacoustic sound transmission system that is stable in any (passive) acoustic environment.

Active electroacoustic systems are commonly employed to transmit sound from one location to another. For example, consider the following configuration: a person talks into a microphone, which produces an electrically amplified signal for driving a loudspeaker, and the loudspeaker induces an output acoustic signal allowing someone else at a more distant location to hear the person talking. Unfortunately, such system designs typically do not consider acoustic feedback, which can destabilize the system and result in “howling.” In contrast, a feedback control system can transmit sound from one location to another using collocated microphone/loudspeaker transducers without the risk of howling. We design feedback controllers that model positive real (i.e., passive) systems, such as a spring and a gyrator. The spring controller essentially binds the diaphragms of the two transducers together. We relate the spring controller to the string connecting two tin cans together in the classical tin can telephone. Measurements are performed on a real feedback control system with two transducers. Because the feedback controller models a passive system, it is stable in any (passive) acoustic environment. [Sennheiser Electronic Corporation helped support this work.]

Hearing aid with an optical microphone

A hearing aid is provided. The hearing aid includes at least one optical microphone. The at least one optical microphone comprises an acoustic-optical transformer for transforming an acoustic input signal into an optical signal, the optical signal is processed in the hearing aid using an optical signal processing unit, and the processed optical signal is transformed into an acoustic output signal using an opto-electrical transformer.

Power-saving mode for hearing aids

Hearing aid wearers can find themselves in situations in which the necessary replacement and/or recharging of a discharged voltage source is not immediately possible. In such a situation, reducing the low-frequency signal elements in the acoustic output signal allows a type of emergency mode to be maintained for a certain period. The majority of important acoustic information thus remains comprehensible to the hearing aid wearer.