Thisobservation allowsusto ob- driven passivelinear oscillator. These conclusionsare con- J. An example of a system that the signal,it is certainlynot a sufficient one,andthat an will yielda positive answer to theabovequestion is onein additional necessary condition is that the signalhasa nar- whichnoise,afterrectification andlow-pass filtering,isused row band frequency spectrum. In the The nonlinearnetworkof Fig. It can be rigorously shown that, isthatof a saturating nonlinearity. If thisnetworkisdriven when the input of a zero-memory nonlinear system is Gaus- byGaussian whitenoiseofsufficiently largeamplitude, the sian,andtheoutputofthesystem issubjected to a sufficient- resulting outputdensity function histogram ofvoltageval- ly narrow-band filtering,thenthisfilteredoutputis again ues shownin Fig.
We seefrom producea Gaussiandisplacement distribution. Forillustrative purposes, weconsider a particularphys- ical realizationof the noise-driven Duffingsystemdiscussed IV.
Forthissystem, thecurrenti playstheelec- We nextconsiderseveralexamplesof nonlinearoscilla- tricalanalogof the velocityJcin Eq. Thenonlinear nal Gaussian white noise sources. Since these oscillators are capacitancewasmadeupof variable capacitance double diodes PhilipsBB in parallel,andtheresonance curve comprised ofentirelypassive elements,theywill notproduce for thefilterisshownin Fig. Thisresonance curvehasthe self-sustaining oscillations. We thuschoose to referto these oscillatorsas "nonlinearpassivefilters.
We plot in Fig. As previoussection. We describethis classof "filters" by the differentialequation wouldbe expected from Eq. We showin Fig. We have also numerically studied the effectsof includingthe passivenonlineardampingwhich is alsopres- 2 4 6 8 10 12 ent in the Furst-Lapid cochlearmodel, and have found a f kHz Gaussian-likedistributionevenin this case.
Finally, we have FIG. Input-output characteristics for a particularphysicalrealizationof includedthe Furst-Lapid type nonlinearstiffnessand non- a Duffing-typenonlinearoscillator,asdescribedin the text. In a reply to a commentby Returning to Eq.
This by the model would be a noise-disturbedsine wave, which observationis sufficientto rule out a particular nonlinear from the aboveconsiderations appearsto bein error. In particular, the author constructs a one-dimensional transmission line coch- 1.
As an instructiveexample, we supposethat g x is 0. Displacementdistributionfor noise-drivenoscillatorwith linear Duffing oscillatordescribedin the text.
As expectedfrom the theory, the damping andnonlinearstiffness of thetypeproposedby FurstandLapid velocitydistributionis well fit by a Gaussiandistribution solid line , but To understandthe effectsof the bandpass filter, with k and k' being positiveconstants[for a discussionof it is sufficientto observethat the oscillatorspendsmuch of this systemin the absenceof noise,see,for example,Gucken- its time in the two stablemodesduring which the signal heimer and Holmes ].
The variation ofg x withx is qualitativelydiffersin the two statesby only a dcoffset. Thus shownin Fig. This is,in potential G x in Fig. We also tion is bandpassfilteredand then histogramed. As before, for a sufficientlyweak noisesource,the In general,there are three identifiablemodesof oscilla- systemwill spendmuch of its time oscillatingin oneof its tion for this system,as can be seen in Fig.
Thesemodescan, in general,have different displaysa typicalsampleof the numericallyintegratedsolu- natural frequenciesof oscillation,and somemodesmay be tion for this system.
When the output of the filter is driven linear oscillator. Additionally, there will be time in- bandpassfiltered about the natural frequencyof one of its tervalswherenoisefluctuationsare largeenoughto drive the oscillationmodes,the dc offsetsamongthe variousmodes oscillator out of thesestable oscillation modes,and the sys- will be removedfrom the signal,as well as signalcompo- tem will consequentlyspenda shorttime oscillatingthrough nentsfrom all of thosemodesthat are not degenerate or the regioncontainingboth stablepoints,beforesettlingback nearlydegenerate in frequencywith the centralfrequency down into one of the two stablemodesagain.
From this ob- of the bandpassfilter. In Fig. We have thus demonstrated that a broad class of noise- 24 for different choicesof the level of the noise source. Similar conclusions bandpass filterbeforethe histograming is performed a pro- have been reached using approximationmethods con- cerningpassiveoscillatorswith nonlinear stiffnessthat fall outside of this class.
Some of 0 the featuresof the SOAE data may be qualitativelyfit with -2 -1 0 1 2 -2 -1 0 1 2 passivemodels,but, to date, no passiveSOAE model has x x beenshownto giveboth a narrow-bandspectrumaswell as c 2. The data FIG. Note that for determiningthe essentialcharacterof the generating the output signalsof this oscillatorhavenot beennarrow-bandfilteredbe- mechanisms.
If this operationis performed,the two "Gaussian- like" peaksare collapsedto the origin,and we obtaina singleGaussian-like SOAEs and other typesofcochlearemissions,which are peak. Duifhuis, J. Horst, and H. Wit mechanisms. Academic, London , pp. Middleton, D. Millman, J. Nayfeh, A. Nonlinear Oscillations Wiley, 3 b. Furst, and Savithri Sivaramakrishnan for their contribu- Parlitz, U.
This work was supportedin A, Sur lescourbesdbfiniesparunebquationdi. Oeuvres Vol. Topicsin the Theoryof Random Noise, Vol. I Gordon and Breach,New York , pp. It isexactly Talmadge,C. Handbook of Mathematical sponseduring reversiblechangesinducedby aspirinconsumption,"in Functions Dover, New York , pp. Kemp Plenum, New York , pp. Wit Academic,London , pp. Non-Linear Mechan- van Dijk, P.
Furst, M. Gold, T. The physicalbasisof the actionof the coch- Wit, H. London, Ser. Patient response is not needed. Training is quick and extremely intuitive. The results showed a statistically significant asymmetric mean amplitude response in favor of the right ear, the females, the high frequency bands and the newborns with higher post-conception age.
Ero-Scan contains memory to store tests. Esto crea un producto derivado que puede detectarse y medirse: Development of cochlear active mechanisms in humans differs between gender.
Arch Otoraryngol Head Neck Surg ; Universal newborn hearing screening using transient evoked otoacoustic emissions: Evidence of peripheral hearing asymetry in humans: Transient evoked otoacoustic emissions TEOAE have been widely used in neonatal hearing screening programs. Un minimo de emissles por carga 20 horas de tiempo Interfaz del usuario: Functional maturation of cochlear active mechanisms and of the medial olivocochlear system in humans.
Growth of evoked otoacoustic emissions during the first days postpartum. The use of transient evoked otoacoustic emissions in neonatal hearing screening programs. El Software de la base de datos del Ero-Scan es una herramienta de manejo de datos que complementa el Ero-Scan de Maico. The remote probe makes it easy to maneuver around the head of your patient to attain a tight ear seal.
How to cite this article. A speculation about the parallel ear asymetries and sex differences in hearing sensitivity and otoacoustic emissions. Artigo recebido em 08 de agosto de Characteristics of transient evoked otoacoustic emissions TEOEs in neonates. JavaScript seems to be disabled in ootacusticas browser. Etiquetas de Produtos Adicionar as suas etiquetas: You must have JavaScript enabled in your browser to utilize the functionality of this website.
Sexual dimorphism and the development of the human cochlea. This website uses cookies to improve your experience while you navigate through the website. Out of these cookies, the cookies that are categorized as necessary are stored on your browser as they are as essential for the working of basic functionalities of the website.
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