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1.
The features of the first-passage-time density function are analyzed theoretically in terms of synchronization between noise and periodic signal in a symmetric double-square-well system. Resonance is demonstrated as a maximum synchronization between them. To have the maximum cooperation between signal and noise, it is shown that the noise strength at resonance should increase linearly with the frequency of the signal. The time scale of the process at resonance is also shown to increase linearly with the period of the signal. 相似文献
2.
It is shown that the single-step periodic signal (periodic telegraph signal) can not produce coherent stochastic resonance for diffusion on a segment with one absorbing and one reflecting end points while the multi-step periodic signal does. The general features of this process are exihibited. The resonant frequency is found to decrease and the mean first passage time at resonant frequency increases linearly, as we increase the length of the medium. The cycle variable is shown to be the proper argument to express the first passage probability at resonance. A formula for first passage probability at resonance is derived in terms of two universal functions, which clearly isolates its dependence on the length of the medium. 相似文献
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输入信号和噪声对单模激光随机共振的影响 总被引:3,自引:1,他引:2
采用色抽运噪声和实虚部间关联的量子噪声驱动的单模激光损失模型,运用线性化近似方法计算了周期性信号加性输入时激光系统的输出光强信噪比,发现用信噪比与量子噪声实虚部间关联系数的关系曲线描述的随机共振现象.在抽运噪声自关联为短时关联情况下,当信号振幅增大和频率增快、抽运噪声色关联时间增大时,系统的随机共振加强;而噪声强度的增加会削弱系统的随机共振.在抽运噪声自关联为长时关联情况下,当信号振幅增大和量子噪声强度减弱时,系统的随机共振加强;而信号频率、抽运噪声强度、抽运噪声色关联时间的变化对系统随机共振的影响很小. 相似文献
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Summary We consider the transmission of a periodic signal by noisy threshold devices. A general expression for the input-output characteristic
is developed and applied to two particular threshold devices. It is shown that the amplitude of the signal output shows in
the subthreshold regime a maximum as a function of the noise strength—the fingerprint of stochastic resonance.
Paper presented at the International Workshop ?Fluctuations in Physics and Biology: Stochastic Resonance, Signal Processing
and Related Phenomena?, Elba 5–10 June 1994. 相似文献
7.
Stochastic resonance (SR) in an over-damped linear system subjected to an excitation of bias signal modulated noise with multiplicative and additive noises is investigated. We obtain the exact expressions of the first two moments and the signal-to-noise ratio (SNR) of the output by using linear-response theory. The SNR depends non-monotonically on the intensity and the correlation time of multiplicative noise, the correlation time of additive noise, the intensity of the cross noise between multiplicative and additive noise, as well as the external field frequency. The conventional SR, the SR in a broad sense and the bona fide SR are found in the system. The influences of the asymmetries of multiplicative and additive noise, the correlation rate of the cross noise, the intensity of additive noise, the amplitude of signal and the bias on the SNR are analyzed. Moreover, we pointed out that SR can be realized by tuning the system parameter with fixed noise, i.e., parameter-induced stochastic resonance (PSR) exists. 相似文献
8.
Monte Carlo and numerical studies of coloured noise and stochastic resonance problems 总被引:1,自引:0,他引:1
Claudia Berghaus Angela Hilgers Jürgen Schnakenberg 《Zeitschrift für Physik B Condensed Matter》1996,100(1):157-163
We suggest two algorithms for evaluating dynamical systems described as first order differential equations under the influence of external noise represented by an Ornstein-Uhlenbeck process: a direct Monte Carlo simulation of the equation of motion and a numerical integration of the associated composite marcov equation. The two algorithms complement one another with respect to small and large noise correlation times and produce results which agree within any desired accuracy. We apply our algorithms to the problem of stochastic resonance and present the numerical results of first passage time densities, transition rates und phase histograms as functions of the system parameters frequency of the periodic force, noise correlation time and noise strength. 相似文献
9.
Stochastic resonance in a bias linear system with multiplicative and additive noise 总被引:7,自引:0,他引:7
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In this paper, the stochastic resonance in a bias linear system
subjected multiplicative
and additive dichotomous noise is investigated. Using the linear-response
theory and the properties of the dichotomous noise, this paper finds
the exact expressions
for the first two moments and the signal-to-noise ratio
(SNR). It is shown that the SNR is a non-monotonic function of the
correlation time of the multiplicative and additive noise, and it varies
non-monotonously with the intensity and asymmetry of the multiplicative
noise as well as the external field frequency. Moreover, the SNR depends on
the system bias, the intensity of the cross noise between the multiplicative
and additive noise, and the strength and asymmetry of the additive noise. 相似文献
10.
J. Granwehr 《Applied magnetic resonance》2007,32(1-2):113-156
The signal in a nuclear magnetic resonance (NMR) experiment is highly sensitive to fluctuations of the environment of the
sample. If, for example, the static magnetic field B
0, the amplitude and phase of radio frequency (rf) pulses, or the resonant frequency of the detection circuit are not perfectly
stable and reproducible, the magnetic moment of the spins is altered and becomes a noisy quantity itself. This kind of noise
depends on the presence of a signal, to which it is usually proportional. Since all the spins at a particular location in
a sample experience the same environment at any given time, such multiplicative noise primarily affects the reproducibility
of an experiment. It is mainly of importance in the indirect dimensions of a multidimensional experiment, when intense lines
are suppressed with a phase cycle, or for difference spectroscopy techniques. Equivalently, experiments which are known to
be problematic with regard to their reproducibility, like flow experiments or experiments with a mobile target, tend to be
affected more strongly by multiplicative noise. In this article it is demonstrated how multiplicative noise can be identified
and characterized using very simple, repetitive experiments. An error estimation approach is developed to give an intuitive,
yet quantitative understanding of its properties. The consequences for multidimensional NMR experiments are outlined, implications
for data analysis are shown, and strategies for the optimization of experiments are summarized.
Author's address: Josef Granwehr, Sir Peter Mansfield Magnetic Resonance Center, School of Physics and Astronomy, Univesity
of Nottingham, Nottingham NG7 2RD, UK 相似文献
11.
ZHANG Liang-Ying CAO Li WU Da-Jin 《理论物理通讯》2008,49(5):1310-1314
A single-mode laser noise model driven by quadratic colored pump noise and amplitude modulation signal is proposed. The real and imaginary
parts of the pump noise are assumed to be cross-correlation. The effect of
cross-correlation of noise and amplitude modulation of signal on laser
statistical properties is studied by using the linearized approximation. The
analytic expression of signal-to-noise ratio (SNR) is calculated. It is
found that the phenomena of stochastic resonance (SR) respectively exist in the
curves of the SNR versus the noise cross-correlation coefficient λ
and the SNR versus the pump parameter a, as well as the SNR versus the
signal frequency
ω in our model. It is shown that there are three different typies of SR in the model: the conventional form of SR, the SR in the broad sense, and the bona fide SR. 相似文献
12.
Stochastic resonance, reverse-resonance, and resonant activation induced by a multi-state noise 总被引:1,自引:0,他引:1
Jing-hui Li 《Physica A》2010,389(1):7-3266
In this paper, we investigate the periodic response for a linear system driven by a multiplicative multi-state noise (which is composed of the multiplication of two dichotomous noises) to an input temporal oscillatory signal, and the escape of Brownian particles over the fluctuating potential barrier for a system with a piece-wise linear potential and driven by an additive multi-state noise (which is also composed of the multiplication of two dichotomous noises). For the first system, we get the stochastic resonance phenomenon for the amplitude of the periodic response vs. the two dichotomous noise strengths, and the phenomenon of reverse-resonance for the amplitude of the periodic response vs. k, which represents the asymmetry degree of the dichotomous noises. For the second system, we obtain the resonant activation phenomenon, for which the mean first passage time of the Brownian particles over the fluctuating potential barrier shows a minimum as the function of the transition rates of the multi-state noise. 相似文献
13.
The stochastic resonance phenomenon in a bistable system subject to Markov dichotomous noise (DN) is investigated. Based on the adiabatic elimination and the two-state theories, the explicit expressions for the signal-to-noise ratio (SNR) and the spectral power amplification (SPA) have been obtained. It is shown that two peaks can occur on the curve of SNR versus the intensity of the DN. Moreover, the SNR is a non-monotonic function of the correlation time of the DN. The SPA varies non-monotonously with the strength of the DN. The dependence of the SNR on the frequency and the amplitude of the external periodic signal are discussed. The effect of the external frequency and the correlation time of the DN on the SPA are analyzed. 相似文献
14.
Summary We study the signal-to-noise ratio, signal and noise output levels in a fast bistable electronic system: a tunnel diode. We
observe stochastic resonance when the system is driven by a sum of a small periodic signal and noise. The phenomenon is investigated
for values of the driving frequency as high as 10 kHz. This is the highest frequency value used in SR experiments until now.
In the presence of ?white noise?, we observe a nonmonotonic behavior characterized by a sharp dip in the output noise level
measured at 100Hz and 1 kHz. A similar behavior is predicated by recent theories. We also present preliminary experimental
results of SR in the presence of an Ornstein-Uhlenbeck noise. For the set of investigated values of the correlation time of
the noise, we still observe the characteristic dip in the output noise levels. The height of the dip is affected by the correlation
time of the noise.
Paper presented at the International Workshop ?Fluctuations in Physics and Biology: Stochastic Resonance, Signal Processing
and Related Phenomena?, Elba, 5–10 June 1994. 相似文献
15.
Acoustic vibration of the amphibian eardrum studied by white noise analysis and holographic interferometry 总被引:3,自引:0,他引:3
M Anson A C Pinder M J Keating S H Chung 《The Journal of the Acoustical Society of America》1985,78(3):916-923
The motion of the amphibian eardrum under free-field acoustic stimulation was investigated using time-averaged holography. We show that the amplitude is linearly related to sound pressure up to +/- 1000 nm. The frequency response of the eardrum shows broad resonance characteristics with a main peak between 1200-2200 Hz. The velocity of the tympanic membrane's motion at its resonance frequency matches the acoustic velocity of air particles. The resonance characteristics of the eardrum are also revealed by white noise stimulation. The power spectrum obtained by Fourier transformation of the autocorrelation of the response to noise resembles closely that obtained by holography. 相似文献
16.
较之于线性噪声, 非线性噪声更广泛地存在于实际系统中, 但其研究远不能满足实际情况的需要. 针对作为非线性阻尼涨落噪声基本构成成分的二次阻尼涨落噪声, 本文考虑了周期信号与之共同作用下的线性谐振子, 关注这类具有基本意义的阻尼涨落噪声的非线性对系统共振行为的影响. 利用Shapiro-Loginov公式和Laplace变换推导了系统稳态响应振幅的解析表达式, 并分析了稳态响应振幅的共振行为, 且以数值仿真验证了理论分析的有效性. 研究发现: 系统稳态响应振幅关于非线性阻尼涨落噪声系数具有非单调依赖关系, 特别是非线性阻尼涨落噪声比线性阻尼涨落噪声更有助于增强系统对外部周期信号的响应程度; 而且, 非线性阻尼涨落噪声比线性阻尼涨落噪声使得稳态响应振幅关于噪声强度具有更为丰富的共振行为; 同时, 二次阻尼涨落噪声使得稳态响应振幅关于系统频率出现真正的共振现象; 而在这些现象和性质中, 非线性噪声项的非线性性质对共振行为起着关键的作用. 显然, 以二次阻尼涨落作为基本形式引入的非线性阻尼涨落噪声, 可以有助于提高微弱周期信号检测的灵敏度和实现对周期信号的频率估计. 相似文献
17.
We demonstrate experimentally an atomic magnetometer based on optical pumping theory, a magnetic resonance that is induced by a radio frequency field and dependent on the magnetic field strength. Compared with the conventional method using one radiation field, which is used not only as the probe beam but also as a pump beam, the additional re-pump beam can increase remarkably the amplitude of the signal. It is shown that the amplitude of the magnetic field resonance signal can increase more than 55% by using an additional re-pump beam, which makes the sensitivity of the magnetometer higher. Finally, we investigate the relation between amplitude of the signal and re-pump laser power, and calculate the atomic population in the trapping states with rate equations. 相似文献
18.
Stochastic resonance(SR) is studied in an under-damped bistable system driven by the harmonic mixing signal and Gaussian white noise. Using the linear response theory(LRT), the expressions of the spectral amplification at fundamental and higher-order harmonic are obtained. The effects of damping coefficient, noise intensity, signal amplitude, and frequency on spectral amplifications are explored. Meanwhile, the power spectral density(PSD) and signal-to-noise ratio(SNR) are calculated to quantify SR and verify the theoretical results. The SNRs at the first and second harmonics exhibit a minimum first and a maximum later with increasing noise intensity. That is, both of the noise-induced suppression and resonance can be observed by choosing proper system parameters. Especially, when the ratio of the second harmonic amplitude to the fundamental one takes a large value, the SNR at the fundamental harmonic is a monotonic function of noise intensity and the SR phenomenon disappears. 相似文献
19.
A linear system driven by correlated asymmetric dichotomous noises and periodic signal was investigated in the overdamped
case. The exact expressions of output signal amplitude and signal-to-noise ratio (SNR) of the system were derived. By means
of numerical calculations, we found that: (i) At some fixed multiplicative noise intensities, the output signal amplitude
with frequency exhibits the structure of a weak peak, even no peak as the dichotomous noise is asymmetric; (ii) In the case
of asymmetric dichotomous noise, the signal frequency can cause non-monotonous behavior of the output signal amplitude with
respect to multiplicative noise intensity; (iii) The curve of SNR with frequency has a weak peak and a trough in the case
of symmetric dichotomous noise, but no peak with asymmetric; (iv) Whether the multiplicative noise is symmetric or asymmetric,
the noise can enhance response of the system; (v) The SNR increases with the correlation strength between the two noises decreasing.
In addition, the plane of multiplicative noise intensity versus noise symmetric parameter was plotted. 相似文献