scholarly journals Study of rogue wave by low-pass filtered noise in a multistable fiber laser

2013 ◽  
Vol 23 ◽  
pp. 23-26
Author(s):  
R. Sevilla Escoboza ◽  
G. Huerta Cuéllar ◽  
J. García López ◽  
D. López Mancilla ◽  
C. Castañeda Hernández ◽  
...  
Keyword(s):  
Fiber Laser ◽  
Rogue Wave ◽  
Low Frequency ◽  
Pump Current ◽  
Rogue Waves ◽  
High Amplitude ◽  
Frequency Noise ◽  
Level Laser ◽  
Low Pass ◽  
Filtered Noise

Clear evidence of rogue waves in a multistable system is revealed with an erbium-doped fiber laser driven by harmonic pump modulation (Pisarchik, Jaimes-Reátegui, Sevilla-Escoboza, Huerta-Cuellar & Taki, 2011). We demonstrate numerically and experimentally that a low-pass noise filtering can control the probability for the appearance of a particular state. The results of numerical simulations with the use of a three-level laser model display good agreement with experimental results. The mechanism for the rogue wave formation lies in the interplay of stochastic processes with multistable deterministic dynamics. Low-frequency noise applied to a diode pump current induces rare jumps to coexisting subharmonic states with high-amplitude pulses perceived as rogue waves. The probability of these events depends on the noise filtered frequency and grows up when the noise amplitude increases. The probability distribution of spike amplitudes confirms the rogue wave character of the observed phenomenon.

Rogue Wave and Breather Structures with “High Frequency” and “Low Frequency” in 𝒫𝒯-Symmetric Nonlinear Couplers with Gain and Loss

2016 ◽  
Vol 71 (10) ◽  
pp. 961-969 ◽  
Author(s):  
Dang-Jun Yu ◽  
Jie-Fang Zhang
Keyword(s):  
High Frequency ◽  
Rogue Wave ◽  
Low Frequency ◽  
Zero Solution ◽  
Rogue Waves ◽  
Transformation Method ◽  
Rational Solutions ◽  
Plane Wave Solution ◽  
Gain And Loss ◽  
Basic Characteristics

AbstractBased on the modified Darboux transformation method, starting from zero solution and the plane wave solution, the hierarchies of rational solutions and breather solutions with “high frequency” and “low frequency” of the coupled nonlinear Schrödinger equation in parity-time symmetric nonlinear couplers with gain and loss are constructed, respectively. From these results, some basic characteristics of multi-rogue waves and multi-breathers are studied. Based on the property of rogue wave as the “quantum” of pattern structure in rogue wave hierarchy, we further study the novel structures of the superposed Akhmediev breathers, Kuznetsov-Ma solitons and their combined structures. It is expected that these results may give new insight into the context of the optical communications and Bose-Einstein condensations.

Required Data Collection Times for Steady and Quasi-steady Experiments

2017 ◽  
Author(s):  
Robert F. Roddy ◽  
David E. Hess
Keyword(s):  
High Frequency ◽  
Low Frequency ◽  
Frequency Noise ◽  
Surface Ship ◽  
System A ◽  
Low Pass ◽  
Collection Period ◽  
Almost All ◽  
Low Pass Filters

One of the requirements in performing steady or quasi-steady experiments is the determination of adequate collection times so that the data will not be biased due to low frequency energy in the data stream. Since virtually all steady experiments run at DTMB have low pass filters in line with the signal conditioning, high frequency noise is not a consideration in determining the required collection times. At both EMB and DTMB almost all of the surface ship drag measurements were made using gravity type balances until about 1970. These balances used both springs and dampers to modify the natural frequency of the system so that a good average model drag could be determined in a 5-6 sec collection period. Submarine model experiments began using block gages to measure drag beginning in the late 1950's. For these experiments crude methods were used to damp the output data but, to the author’s knowledge, no methods were ever put into place that was analogous to the springs and damper system. A method for determining the required collection times for any steady or quasi-steady experiment is presented along with sample cases showing the necessity for, and the utility of, using such a method.

Low-frequency noise suppression of a fiber laser based on a round-trip EDFA power stabilizer

Laser Physics ◽  
2013 ◽  
Vol 23 (3) ◽  
pp. 035105 ◽  
Author(s):  
Z Q Pan ◽  
J Zhou ◽  
F Yang ◽  
Q Ye ◽  
H W Cai ◽  
...  
Keyword(s):  
Fiber Laser ◽  
Noise Suppression ◽  
Low Frequency ◽  
Frequency Noise ◽  
Low Frequency Noise ◽  
Round Trip ◽  
Power Stabilizer

Construction of a High-Pass Digital Filter from a Low-Pass Digital Filter

1994 ◽  
Vol 10 (4) ◽  
pp. 374-381 ◽  
Author(s):  
Stephen D. Murphy ◽  
D. Gordon E. Robertson
Keyword(s):  
Digital Filter ◽  
Low Frequency ◽  
Frequency Noise ◽  
Band Pass Filter ◽  
Low Frequency Noise ◽  
Pass Filter ◽  
Low Pass Filter ◽  
High Pass Filter ◽  
Low Pass ◽  
High Pass

To remove low-frequency noise from data such as DC-bias from electromyo-grams (EMGs) or drift from force transducers, a high-pass filter was constructed from a low-pass filter of known characteristics. A summary of the necessary steps required to transform the low-pass digital were developed. Contaminated EMG and force platform data were used to test the filter. The high-pass filter successfully removed the low-frequency noise from the EMG signals. The high-pass filter was then cascaded with the low-pass filter to produce a band-pass filter to enable simultaneous high- and low-frequency noise reduction.

scholarly journals Control of attractor preference by low-pass filtered noise in a multistable fiber laser*

2012 ◽  
Vol 45 (12) ◽  
pp. 232-236
Author(s):  
G. Huerta-Cuellar ◽  
R. Jaimes-Reátegui ◽  
R. Sevilla-Escoboza ◽  
J.H. García-López ◽  
D. López-Mancilla ◽  
...  
Keyword(s):  
Fiber Laser ◽  
Low Pass ◽  
Filtered Noise

Uncertainty Analysis in Ship-Model Resistance Test

2015 ◽  
Author(s):  
Sverre Steen ◽  
Ankit ◽  
Sergey Gavrilin
Keyword(s):  
Time Window ◽  
Time Windows ◽  
Low Frequency ◽  
High Amplitude ◽  
Mean Value ◽  
Frequency Noise ◽  
Multiple Time ◽  
Ship Model ◽  
Force Data ◽  
Multiple Time Windows

In a ship model resistance test, the towing force measurements usually contain high amplitude and low frequency noise. The length of the towing tank is finite, which induces an uncertainty in the estimated mean value of the towing force. In practical work, a time-window is manually selected from the complete measurement time history to compute the mean value to be used in the further analysis. Due to the combination of high-amplitude, low frequency noise and limited length of time series, the selection of the time window is found to matter for the resulting mean value. The idea pursued in this paper is that the uncertainty in the estimated mean value of resistance can be improved by considering multiple time windows rather than just one. First, the paper deals with the estimation of mean value of resistance from the given towing force data using 1) Single Time Window (STW) technique 2) Multiple Time Windows (MTW) technique. By applying these techniques to a given time series with a known mean, we can compare reliability of these estimators. Finally, the carriage and ship model are mathematically modeled as moving spring-mass-damper system. Comparison of the simulated towing force data with the experimental data allows us to understand the major sources of noise in towing force data.

Pulse-shape distortion introduced by broadband deconvolution

1992 ◽  
Vol 82 (1) ◽  
pp. 238-258
Author(s):  
Stuart A. Sipkin ◽  
Arthur L. Lerner-Lam
Keyword(s):  
Transfer Function ◽  
Ground Motion ◽  
Low Frequency ◽  
Frequency Noise ◽  
Low Frequencies ◽  
Pass Filter ◽  
Long Period ◽  
High Pass Filter ◽  
Low Pass ◽  
High Pass

Abstract The availability of broadband digitally recorded seismic data has led to an increasing number of studies using data from which the instrument transfer function has been deconvolved. In most studies, it is assumed that raw ground motion is the quantity that remains after deconvolution. After deconvolving the instrument transfer function, however, seismograms are usually high-pass filtered to remove low-frequency noise caused by very long-period signals outside the frequency band of interest or instabilities in the instrument response at low frequencies. In some cases, data must also be low-pass filtered to remove high-frequency noise from various sources. Both of these operations are usually performed using either zero-phase (acausal) or minimum-phase (causal) filters. Use of these filters can lead to either bias or increased uncertainty in the results, especially when taking integral measures of the displacement pulse. We present a deconvolution method, based on Backus-Gilbert inverse theory, that regularizes the time-domain deconvolution problem and thus mitigates any low-frequency instabilities. We apply a roughening constraint that minimizes the long-period components of the deconvolved signal along with the misfit to the data, emphasizing the higher frequencies at the expense of low frequencies. Thus, the operator acts like a high-pass filter but is controlled by a trade-off parameter that depends on the ratio of the model variance to the residual variance, rather than an ad hoc selection of a filter corner frequency. The resulting deconvolved signal retains a higher fidelity to the original ground motion than that obtained using a postprocess high-pass filter and eliminates much of the bias introduced by such a filter. A smoothing operator can also be introduced that effectively applies a low-pass filter. This smoothing is useful in the presence of blue noise, or if inferences about source complexity are to be made from the roughness of the deconvolved signal.

Low Frequency-Noise Random Fiber Laser With Bidirectional SBS and Rayleigh Feedback

2015 ◽  
Vol 27 (5) ◽  
pp. 490-493 ◽  
Author(s):  
Bhavaye Saxena ◽  
Zhonghua Ou ◽  
Xiaoyi Bao ◽  
Liang Chen
Keyword(s):  
Fiber Laser ◽  
Low Frequency ◽  
Frequency Noise ◽  
Low Frequency Noise

scholarly journals Low-Voltage Low-Pass and Band-Pass Elliptic Filters Based on Log-Domain Approach Suitable for Biosensors

Sensors ◽  
2019 ◽  
Vol 19 (24) ◽  
pp. 5581
Author(s):  
Pipat Prommee ◽  
Natapong Wongprommoon ◽  
Montree Kumngern ◽  
Winai Jaikla
Keyword(s):  
Low Voltage ◽  
Random Noise ◽  
Low Frequency ◽  
Frequency Noise ◽  
Bipolar Junction Transistor ◽  
Low Pass ◽  
Junction Transistor ◽  
Band Pass ◽  
Electronically Tunable ◽  
Log Domain

This research proposes bipolar junction transistor (BJT)-based log-domain high-order elliptic ladder low-pass (LPF) and band-pass filters (BPF) using a lossless differentiator and lossless and lossy integrators. The log-domain lossless differentiator was realized by using seven BJTs and one grounded capacitor, the lossy integrator using five BJTs and one grounded capacitor, and the lossless integrator using seven BJTs and one grounded capacitor. The simplified signal flow graph (SFG) of the elliptic ladder LPF consisted of two lossy integrators, one lossless integrator, and one lossless differentiator, while that of the elliptic ladder BPF contained two lossy integrators, five lossless integrators, and one lossless differentiator. Log-domain cells were directly incorporated into the simplified SFGs. Simulations were carried out using PSpice with transistor array HFA3127. The proposed filters are operable in a low-voltage environment and are suitable for mobile equipment and further integration. The log-domain principle enables the frequency responses of the filters to be electronically tunable between 10k Hz–10 MHz. The proposed filters are applicable for low-frequency biosensors by reconfiguring certain capacitors. The filters can efficiently remove low-frequency noise and random noise in the electrocardiogram (ECG) signal.

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