scholarly journals Optimizing the Amplifier Bandwidth for Pulse Reception

2021 ◽  
Author(s):  
Russell Kurtz
Keyword(s):  
Pulse Width ◽  
Signal To Noise Ratio ◽  
Lowpass Filter ◽  
Gaussian Shape ◽  
Temporal Shift ◽  
Filter Bandwidth ◽  
Pulse Distortion ◽  
The Relationship ◽  
Potential Rate ◽  
Key Parameter

<p>Detecting and recognizing pulses is a critical task, in fields as widely separated as telecommunications, lidar, and target illumination. In all cases, the signal-to-noise ratio (SNR) is a key parameter that can be used to determine both the potential rate of errors and the probability of correct detection. In this paper the relationship among pulse width, amplifier bandwidth, and SNR is determined through modeling four approximations to pulse shapes and four amplifier lowpass filter configurations. The analysis determined that, given a specific filter and pulse shape, the bandwidth that maximizes SNR is a constant divided by the pulse width. For example, if the pulse has a Gaussian shape and the amplifier incorporates a second-order Chebyshev lowpass filter, this constant is 0.3389. Applying this, if the pulse width is 20 ns the maximum SNR comes for a filter bandwidth of 16.95 MHz, while if the pulse width is 50 µs the SNR is maximized at a 6.778-kHz bandwidth. Passing the signal through a filter also distorts the signal shape; the temporal shift and pulse lengthening are also determined. The calculated values are offered as inputs to a potential trade space that includes SNR, pulse distortion by the filter, and cost.</p>

scholarly journals Optimizing the Amplifier Bandwidth for Pulse Reception

2021 ◽  
Author(s):  
Russell Kurtz
Keyword(s):  
Pulse Width ◽  
Signal To Noise Ratio ◽  
Lowpass Filter ◽  
Gaussian Shape ◽  
Temporal Shift ◽  
Filter Bandwidth ◽  
Pulse Distortion ◽  
The Relationship ◽  
Potential Rate ◽  
Key Parameter

<p>Detecting and recognizing pulses is a critical task, in fields as widely separated as telecommunications, lidar, and target illumination. In all cases, the signal-to-noise ratio (SNR) is a key parameter that can be used to determine both the potential rate of errors and the probability of correct detection. In this paper the relationship among pulse width, amplifier bandwidth, and SNR is determined through modeling four approximations to pulse shapes and four amplifier lowpass filter configurations. The analysis determined that, given a specific filter and pulse shape, the bandwidth that maximizes SNR is a constant divided by the pulse width. For example, if the pulse has a Gaussian shape and the amplifier incorporates a second-order Chebyshev lowpass filter, this constant is 0.3389. Applying this, if the pulse width is 20 ns the maximum SNR comes for a filter bandwidth of 16.95 MHz, while if the pulse width is 50 µs the SNR is maximized at a 6.778-kHz bandwidth. Passing the signal through a filter also distorts the signal shape; the temporal shift and pulse lengthening are also determined. The calculated values are offered as inputs to a potential trade space that includes SNR, pulse distortion by the filter, and cost.</p>

Pulse-Width Modulated Amplifier for DC Servo System and Its Matlab Simulation

2015 ◽  
Vol 9 (1) ◽  
pp. 625-631
Author(s):  
Ma Xiaocheng ◽  
Zhang Haotian ◽  
Cheng Yiqing ◽  
Zhu Lina ◽  
Wu Dan
Keyword(s):  
Mathematical Model ◽  
Transfer Function ◽  
Input Signal ◽  
Pulse Width ◽  
Rotation Speed ◽  
Servo Motor ◽  
Matlab Simulation ◽  
Pulse Width Modulated ◽  
Signal Changes ◽  
The Relationship

This paper introduces a mathematical model for Pulse-Width Modulated Amplifier for DC Servo Motor. The relationship between pulse-width modulated (PWM) signal and reference rotation speed is specified, and a general model of motor represented by transfer function is also put forward. When the input signal changes, the rotation speed of the servo motor will change accordingly. By changing zeros and poles, transient performance of this system is discussed in detail, and optimal ranges of the parameters is recommended at the end of discussion.

scholarly journals Pulse-Width Multiplexing ϕ-OTDR for Nuisance-Alarm Rate Reduction

Sensors ◽  
2018 ◽  
Vol 18 (10) ◽  
pp. 3509 ◽  
Author(s):  
Xiang Zhong ◽  
Xicheng Gao ◽  
Huaxia Deng ◽  
Shisong Zhao ◽  
Mengchao Ma ◽  
...  
Keyword(s):  
Pulse Width ◽  
Signal To Noise Ratio ◽  
Fusion Algorithm ◽  
Multisensor Data Fusion ◽  
Optical Time Domain Reflectometer ◽  
Light Pulses ◽  
Phase Sensitive ◽  
Evidential Theory ◽  
Vibrating Table ◽  
Optical Time

A pulse-width multiplexing method for reducing the nuisance-alarm rate of a phase-sensitive optical time-domain reflectometer ( ϕ -OTDR) is described. In this method, light pulses of different pulse-widths are injected into the sensing fiber; the data acquired at different pulse-widths are regarded as the outputs of different sensors; and these data are then processed by a multisensor data fusion algorithm. In laboratory tests with a sensing fiber on a vibrating table, the effects of pulse-width on the signal-to-noise ratio (SNR) of the ϕ -OTDR data are observed. Furthermore, by utilizing the SNR as the feature in a feature-layer algorithm based on Dempster–Shafer evidential theory, a four-pulse-width multiplexing ϕ -OTDR system is constructed, and the nuisance-alarm rate is reduced by about 70%. These experimental results show that the proposed method has great potential for perimeter protection, since the nuisance-alarm rate is significantly reduced by using a simple configuration.

scholarly journals Comparative Study of Thyristor vs IGBT Based AC-DC Power Converter

2018 ◽  
Vol 17 (3) ◽  
pp. 89-102
Author(s):  
Md. Saiful Islam ◽  
Md. Rifat-Ul-Karim Shovon ◽  
Abdul Goffar Khan
Keyword(s):  
Comparative Study ◽  
Pulse Width ◽  
Output Voltage ◽  
Harmonic Distortion ◽  
Power Converter ◽  
Wave Shape ◽  
Average Output ◽  
Dc Power ◽  
Voltage Wave ◽  
The Relationship

This paper presents a comparative study of the application of Thyristor versus IGBT in AC-DC controlled power converter. Both simulation and practical experiment have been carried out to test the relationship between the average output voltage (Vdc) with firing angle (α, for Thyristor) and triggering pulse width (, for IGBT). Also the total harmonic distortion (THD) has been observed in both the cases. It is observed that IGBT based power converter introduces more harmonics in the system, in spite of more symmetrical output voltage wave shape.

scholarly journals Graphene slurry based passive Q-switcher in erbium doped fiber laser

2019 ◽  
Vol 8 (4) ◽  
Author(s):  
Siti Nur Fatin Zuikafly ◽  
Nor Farhah Razak ◽  
Rizuan Mohd Rosnan ◽  
Sulaiman Wadi Harun ◽  
Fauzan Ahmad
Keyword(s):  
Pump Power ◽  
Fiber Laser ◽  
Pulse Width ◽  
Peak Power ◽  
Signal To Noise Ratio ◽  
Pulsed Laser ◽  
Laser Cavity ◽  
Signal To Noise ◽  
Maximum Pulse Energy ◽  
Erbium Doped

In this work, a Graphene slurry based passive Q-switcher fabricated from Graphene-Polylactic acid (PLA) filament which is used for 3D printing. To produce the Graphene slurry, the diameter of the filament was reduced and Tetrahydrofuran (THF) was used to dissolve the PLA. The Graphene-THF suspension was drop cast to the end of a fiber ferrule and the THF then evaporated to develop Graphene slurry based SA which is integrated in fiber laser cavity. At threshold input pump power of 30.45 mW, a Q-switched Erbium-doped fiber laser (EDFL) can be observed with the wavelength centered at 1531.01 nm and this remained stable up to a pump power of 179.5 mW. As the pump power was increased gradually, an increase in the repetition rates was recorded from 42 kHz to 125 kHz, while the pulse width was reduced to 2.58 μs from 6.74 μs. The Q-switched laser yielded a maximum pulse energy and peak power of 11.68 nJ and 4.16 mW, respectively. The proposed Graphene slurry based saturable absorber also produced a signal-to-noise ratio of 44 dB indicating a stable Q-switched pulsed laser.

scholarly journals Novel methods of estimating relative pollen productivity: A key parameter for reconstruction of past land cover from pollen records

2019 ◽  
Vol 43 (6) ◽  
pp. 731-753 ◽  
Author(s):  
Yiman Fang ◽  
Chunmei Ma ◽  
M Jane Bunting
Keyword(s):  
Land Cover ◽  
Empirical Data ◽  
Alternative Methods ◽  
Model Parameters ◽  
Value Analysis ◽  
Pollen Productivity ◽  
Tropical China ◽  
The Relationship ◽  
Pollen Records ◽  
Key Parameter

Reconstructing land cover from pollen data using mathematical models of the relationship between them has the potential to translate the many thousand pollen records produced over the last 100 years (over 2300 radiocarbon-dated pollen records exist for the UK alone) into formats relevant to ecologists, archaeologists and climate scientists. However, the reliability of these reconstructions depends on model parameters. A key parameter is Relative Pollen Productivity (RPP), usually estimated from empirical data using ‘Extended R Value analysis’ (ERV analysis). Lack of RPP estimates for many regions is currently a major limitation on reconstructing global land cover. We present two alternatives to ERV analysis, the Modified Davis Method and an iteration method, which use the same underlying model of the relationship between pollen and vegetation to estimate RPP from empirical data, but with different assumptions. We test them in simulation against ERV analysis, and use a case study of a problematic empirical dataset to determine whether they have the potential to increase the speed and geographic range of RPP estimation. The two alternative methods are shown to perform at least as well as ERV analysis in simulation. We also present new RPP estimates from southeastern sub-tropical China for nine taxa estimated using the Modified Davis Method. Adding these two methods to the ‘toolkit’ for land cover reconstruction from pollen records opens up the possibility to estimate a key parameter from existing datasets with less field time than using current methods. This can both speed up the inclusion of more of the globe in past land cover mapping exercises such as the PAGES Landcover6k working group and improve our understanding of how this parameter varies within a single taxon and the factors control that variation.

Review of Recent Research on the Selection of Frequency-Gain Characteristics for Hearing Aids

1980 ◽  
Vol 89 (5_suppl) ◽  
pp. 79-83
Author(s):  
Richard Lippmann
Keyword(s):  
Hearing Aids ◽  
Speech Intelligibility ◽  
Signal To Noise Ratio ◽  
Hearing Aid ◽  
Linear Amplification ◽  
Percentage Points ◽  
Gain Characteristic ◽  
The Relationship ◽  
Fitting Hearing Aids ◽  
Selection Of

Following the Harvard master hearing aid study in 1947 there was little research on linear amplification. Recently, however, there have been a number of studies designed to determine the relationship between the frequency-gain characteristic of a hearing aid and speech intelligibility for persons with sensorineural hearing loss. These studies have demonstrated that a frequency-gain characteristic that rises at a rate of 6 dB/octave, as suggested by the Harvard study, is not optimal. They have also demonstrated that high-frequency emphasis of 10–40 dB above 500–1000 Hz is beneficial. Most importantly, they have demonstrated that hearing aids as they are presently being fit do not provide maximum speech intelligibility. Percent word correct scores obtained with the best frequency-gain characteristics tested in various studies have been found to be 9 to 19 percentage points higher than scores obtained with commercial aids owned by subjects. This increase in scores is equivalent to an increase in signal-to-noise ratio of 10 to 20 dB. This is a significant increase which could allow impaired listeners to communicate in many situations where they presently cannot. These results demonstrate the need for further research on linear amplification aimed at developing practical suggestions for fitting hearing aids.

Analysis of Stress-Induced Birefringence in Nd:YAG Crystal

2007 ◽  
Vol 329 ◽  
pp. 557-562
Author(s):  
Hiroshi Matsuura ◽  
Yasuhiro Kunieda ◽  
Nobuhito Yoshihara ◽  
Tsunemoto Kuriyagawa
Keyword(s):  
Pulse Width ◽  
Continuous Wave ◽  
Extinction Ratio ◽  
Average Power ◽  
Elliptical Polarization ◽  
Laser Efficiency ◽  
Output Wavelength ◽  
Laser Dressing ◽  
The Relationship ◽  
Nd:Yag Crystal

A Nd:YAG crystal having a special structure achieved laser operation with an extinction ratio of over 20 dB, a CW (continuous wave) average power of 6 W, a pulse width of 50 ns, and repetition rates in the range 1 kHz – 10 kHz for an output wavelength of 1064 nm for effectively cooling the crystal for the case of laser dressing. The birefringence induced by the stress applied to the crystal results in the production of elliptical polarization before the Brewster-window and thus decreases the laser efficiency. In this paper, we analyzed the relationship between the distortion and the birefringence in a Nd:YAG crystal and the resulting effect on the laser power.

scholarly journals Time and Frequency Localized Pulse Shape for Resolution Enhancement in STFT-BOTDR

2016 ◽  
Vol 2016 ◽  
pp. 1-10 ◽  
Author(s):  
Linqing Luo ◽  
Bo Li ◽  
Yifei Yu ◽  
Xiaomin Xu ◽  
Kenichi Soga ◽  
...  
Keyword(s):  
Pulse Shape ◽  
Signal To Noise Ratio ◽  
Resolution Enhancement ◽  
Input Pulse ◽  
Rectangular Pulse ◽  
Time Domain Reflectometry ◽  
Frequency Resolution ◽  
Gaussian Shape ◽  
Time Frequency ◽  
New Research

Short-Time Fourier Transform-Brillouin Optical Time-Domain Reflectometry (STFT-BOTDR) implements STFT over the full frequency spectrum to measure the distributed temperature and strain along the optic fiber, providing new research advances in dynamic distributed sensing. The spatial and frequency resolution of the dynamic sensing are limited by the Signal to Noise Ratio (SNR) and the Time-Frequency (T-F) localization of the input pulse shape.T-Flocalization is fundamentally important for the communication system, which suppresses interchannel interference (ICI) and intersymbol interference (ISI) to improve the transmission quality in multicarrier modulation (MCM). This paper demonstrates that theT-Flocalized input pulse shape can enhance the SNR and the spatial and frequency resolution in STFT-BOTDR. Simulation and experiments ofT-Flocalized different pulses shapes are conducted to compare the limitation of the system resolution. The result indicates that rectangular pulse should be selected to optimize the spatial resolution and Lorentzian pulse could be chosen to optimize the frequency resolution, while Gaussian shape pulse can be used in general applications for its balanced performance in both spatial and frequency resolution. Meanwhile,T-Flocalization is proved to be useful in the pulse shape selection for system resolution optimization.

Study on Corner Contact Shock of Gear Transmission by ADAMS Software

2015 ◽  
Vol 778 ◽  
pp. 205-211
Author(s):  
Li He ◽  
Jin Yuan Tang
Keyword(s):  
Penetration Depth ◽  
Impact Velocity ◽  
Impact Force ◽  
Ansys Software ◽  
New Approach ◽  
Adams Software ◽  
Simulation Results ◽  
The Impact ◽  
The Relationship ◽  
Key Parameter

Solving gear meshing impact force problems by using ADAMS software is studied.A pair of tooth meshing model is established based on UG, modal neutral file is generated by using ANSYS software, calculating gear meshing impact after Importing ADAMS. The relationship between the impact velocity and the impact force by taking reasonable key parameter about penetration depth in ADAMS simulation.A new approach for studying gear meshing impact is proposed here, and the simulation results show that ADAMS software is a very useful tool for solving gear corner contact shock problems outside the normal path of action line.

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