Frequency Detection Of Hand Tremors Using Customized Accelerometer

2021 ◽  
Author(s):  
Akeel Al-Kazwini ◽  
Ahmad Halilah ◽  
Aeshah Hendi ◽  
Ibrahim Al-Saeed ◽  
Abdullah Al-Azamat ◽  
...  
Keyword(s):  
Frequency Detection

scholarly journals Design and implementation of a jellyfish otolith-inspired MEMS vector hydrophone for low-frequency detection

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Renxin Wang ◽  
Wei Shen ◽  
Wenjun Zhang ◽  
Jinlong Song ◽  
Nansong Li ◽  
...  
Keyword(s):  
Structural Parameters ◽  
Low Frequency ◽  
Directivity Pattern ◽  
Stress Distributions ◽  
Strong Response ◽  
Underwater Acoustic ◽  
Frequency Detection ◽  
Vector Hydrophone ◽  
Shock Resistance ◽  
Marine Applications

AbstractDetecting low-frequency underwater acoustic signals can be a challenge for marine applications. Inspired by the notably strong response of the auditory organs of pectis jellyfish to ultralow frequencies, a kind of otolith-inspired vector hydrophone (OVH) is developed, enabled by hollow buoyant spheres atop cilia. Full parametric analysis is performed to optimize the cilium structure in order to balance the resonance frequency and sensitivity. After the structural parameters of the OVH are determined, the stress distributions of various vector hydrophones are simulated and analyzed. The shock resistance of the OVH is also investigated. Finally, the OVH is fabricated and calibrated. The receiving sensitivity of the OVH is measured to be as high as −202.1 dB@100 Hz (0 dB@1 V/μPa), and the average equivalent pressure sensitivity over the frequency range of interest of the OVH reaches −173.8 dB when the frequency ranges from 20 to 200 Hz. The 3 dB polar width of the directivity pattern for the OVH is measured as 87°. Moreover, the OVH is demonstrated to operate under 10 MPa hydrostatic pressure. These results show that the OVH is promising in low-frequency underwater acoustic detection.

scholarly journals Research on the Cooperative Detection of Stochastic Resonance and Chaos for Weak SNR Signals in Measurement While Drilling

Sensors ◽  
2021 ◽  
Vol 21 (9) ◽  
pp. 3011
Author(s):  
Yi Yang ◽  
Fei Li ◽  
Nan Zhang ◽  
Aiqing Huo
Keyword(s):  
Stochastic Resonance ◽  
Scale Transformation ◽  
Attitude Measurement ◽  
Limit Condition ◽  
Duffing System ◽  
Detection Model ◽  
Frequency Detection ◽  
Measurement Signal ◽  
Measurement While Drilling ◽  
Well Trajectory

In the process of drilling, severe downhole vibration causes attitude measurement sensors to be erroneous; the errors will accumulate gradually during the inclination calculation. As a result, the ultimate well path could deviate away from the planned trajectory. In order to solve this problem, this paper utilized the stochastic resonance (SR) and chaos phase transition (CPT) produced by the second-order Duffing system to identify the frequency and estimate the parameters of the signal during measurement while drilling. Firstly, the idea of a variable-scale is introduced in order to reconstruct the frequency of the attitude measurement signal, and an SR frequency detection model based on a scale transformation Duffing system is established in order to meet the frequency limit condition of the SR. Then, an attitude measurement signal with a known frequency value is input into the Duffing chaos system, and the scale transformation is used again to make the frequency value meet the parameter requirement of chaos detection. Finally, two Duffing oscillators with different initial phases of their driving signal are combined in order to estimate the amplitude and phase parameters of the measurement signal by using their CPT characteristics. The results of the laboratory test and the field-drilling data demonstrated that the proposed algorithm has good immunity to the interference noise in the attitude measurement sensor, improving the solution accuracy of the inclination in a severe noise environment and thus ensuring the dynamic stability of the well trajectory.

Weak Signal Frequency Detection Method Based on Generalized Duffing Oscillator

2011 ◽  
Vol 28 (4) ◽  
pp. 040502 ◽  
Author(s):  
Si-Hong Shi ◽  
Yong Yuan ◽  
Hui-Qi Wang ◽  
Mao-Kang Luo
Keyword(s):  
Detection Method ◽  
Duffing Oscillator ◽  
Signal Frequency ◽  
Weak Signal ◽  
Frequency Detection

High-Accuracy Fundamental Frequency Detection in Power System

2011 ◽  
Vol 383-390 ◽  
pp. 4962-4966
Author(s):  
Ling Li ◽  
Guo Bin Jin ◽  
Shao Ping Huang ◽  
Xiao Peng
Keyword(s):  
Power System ◽  
Fundamental Frequency ◽  
Frequency Measurement ◽  
Least Square ◽  
Signal Model ◽  
Least Square Estimation ◽  
Signal Process ◽  
Frequency Detection ◽  
Novel Method ◽  
Subspace Estimation

A novel method on frequency measurement based on improved TLS-ESPRIT (total least square estimation of signal parameters via rotational invariance techniques) is proposed in this paper with the research on fundamental frequency measurement in power system. TLS-ESPRIT is belong to subspace estimation in modern signal process. Noise is included in signal model, so it is independent on noise. But the same multi-poles cannot be taken when signal is in noise and based on TLS-ESPRIT. Multiple poles restoring is presented to take the true poles accurately. It is revealed that fundamental frequency is detected accurately in harmonics, interharmonics, noise and frequency fluctuations and better anti-noise ability in particular better adaptiveness on time varying signal in amplitude by simulation results.

Study on the Performance of Chaotic Oscillator in Weak Signal Detection

2012 ◽  
Vol 263-266 ◽  
pp. 516-520
Author(s):  
Yan Mang Su ◽  
Zhen Bin Gao ◽  
Xiao Zhe Liu ◽  
Na Zheng
Keyword(s):  
Initial Phase ◽  
Signal To Noise Ratio ◽  
Sampling Frequency ◽  
Signal Frequency ◽  
Chaotic Oscillator ◽  
Reference Frequency ◽  
Weak Signal Detection ◽  
Accuracy Rate ◽  
Frequency Detection ◽  
Output Variance

For the frequency detection by using chaotic oscillator, in this paper, the results which are under the influence of the sampling frequency on the basis of theory that the output variance of the system will reach a maximum when the reference frequency equals to the signal frequency are analyzed. Experiments have indicated that the accuracy rate of the results will be improved and the signal to noise ratio (SNR) threshold will be reduced by increasing the sampling frequency to a certain degree. Besides, we have a further research on detecting the frequency of a signal with an initial phase based on the theory mentioned above, simulation experimental results have verified the output variance still has a drastic change when the reference frequency is equal to the signal frequency.

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