Computer Restoration of 2D Medical Diagnostic Signals with Noise Frequency Spectrum

1970 ◽  
Vol 111 (5) ◽  
pp. 133-136
Author(s):  
M. Nikolova ◽  
Tz. Dimitrova
Keyword(s):  
Mathematical Method ◽  
Frequency Spectrum ◽  
Frequency Band ◽  
Low Frequency ◽  
Experimental Results ◽  
Medical Diagnostic ◽  
Noise Frequency ◽  
Influence Of Noise

An application of mathematical method of Aisenberg for restoration of low frequency medical diagnostic signals after influence of noise is described in the paper. The restoration of frequency spectrum of medical diagnostic signals has been done after preliminary analyses of frequency spectrum of signals with noise and disposition of frequency band of noise in the frequency band of information signals. Some experimental results obtained on the base of application of Aisenberg's method for restoration of medical diagnostic signals are described in the paper. Ill. 9, bibl. 8 (in English; abstracts in English and Lithuanian).http://dx.doi.org/10.5755/j01.eee.111.5.374

scholarly journals Experimental Investigation of the Propagation and Attenuation Rule of Blasting Vibration Wave Parameters Based on the Damage Accumulation Effect

2018 ◽  
Vol 2018 ◽  
pp. 1-9 ◽  
Author(s):  
Huaibao Chu ◽  
Xiaolin Yang ◽  
Shuanjie Li ◽  
Weimin Liang
Keyword(s):  
Frequency Band ◽  
Damage Accumulation ◽  
Low Frequency ◽  
Experimental Results ◽  
Vibration Velocity ◽  
Blasting Vibration ◽  
Main Frequency ◽  
Wave Parameters ◽  
Accumulation Effect ◽  
Vibration Wave

The propagation and attenuation rule of blasting vibration wave parameters is the most important foundation of blasting vibration prediction and control. In this work, we pay more attention to the influence of the damage accumulation effect on the propagation and attenuation rule of vibration wave parameters. A blasting damage accumulation experiment was carried out, the ultrasonic wave velocity of the specimens was measured, and the damage value was calculated during the experiment. The blasting vibration wave was monitored on the surface of the specimens, and its energy was calculated by using the sym8 wavelet basis function. The experimental results showed that with the increase in the number of blasts, the damage continues to increase; however, the vibration velocity and the main frequency decrease continuously, the unfocused vibration wave energy in the zone near to the blasting source is rapidly concentrated in the low-frequency band (frequency bands 1 to 3), and the energy is further concentrated in the low-frequency band in the intermediate zone and zone far from the blasting source. There is a distortion process in which the vibration velocity and the main frequency increase slightly and the energy of the blasting vibration wave converges to the high-frequency band (the 5th band) before the sudden unstable fracture failure of the specimens. The experimental results indicate that the prediction and evaluation of blasting vibration should consider the variation rule of blasting vibration wave parameters synthetically based on the cumulative damage effect, and it is not safe to use only one fixed vibration control standard for the whole blasting operation.

A New Advanced Topology of Stacked Multicell Inverter

2014 ◽  
Vol 15 (4) ◽  
pp. 327-333 ◽  
Author(s):  
Mohamad R. Banaei ◽  
M. R. Jannati Oskuee ◽  
F. Mohajel Kazemi
Keyword(s):  
Frequency Spectrum ◽  
Output Voltage ◽  
Low Frequency ◽  
Experimental Results ◽  
The Novel ◽  
Stored Energy ◽  
Well Performance ◽  
Flying Capacitors ◽  
Voltage Frequency ◽  
Simulation Results

Abstract In this paper, a new advanced topology of stacked multicell inverter is proposed which is generally suitable for high number of steps associated with a low number of switches. Compared with traditional flying capacitor multicell and stacked multicell (SM) inverters, doubling the number of output voltage levels and the RMS value, ameliorating the output voltage frequency spectrum, decreasing the number and rating of components, stored energy and rating of flying capacitors are available with the proposed inverter. These improvements are achieved by adding only four low-frequency switches to the traditional SM inverter’s structure. The suggested topology is simulated using MATLAB/SIMULINK software, and simulation results are presented to indicate well-performance of the novel converter. In addition, the experimental results of proposed topology prototype have been presented to validate its practicability.

Experimental Study of Jet Noise Characteristics of Series Connected Nozzles

2005 ◽  
Author(s):  
Qiang Xu
Keyword(s):  
Frequency Spectrum ◽  
Frequency Band ◽  
Low Frequency ◽  
Jet Noise ◽  
Steel Tube ◽  
The Other ◽  
Chamber Pressure ◽  
Band Frequency ◽  
Noise Characteristics ◽  
Frequency Peak

Put abstract text here. A serial of experiments were conducted to study the noise radiated from a series connected nozzle pair. The experiment results are presented in this paper. This nozzle pair consists of two nozzles, one is called source nozzle, and the other is a secondary nozzle. In these experiments, the structure of source nozzle was fixed while that of secondary nozzle was changeable. The source nozzle is mounted on a pressure chamber which is connected to an air compressor. A steel tube is fixed at the tail of source nozzle. The secondary nozzle is connected to the other end of the tube. Throat size of secondary nozzle is larger then that of source nozzle. 15 types of nozzles with different expansion ratio, length of expand segment, and throat structure were used as the secondary nozzle. Jet noise pressure of these nozzle pairs was measured by 40AF Free Field Microphone. The frequency spectrum of jet noise from source nozzle with steel tube under different chamber pressures was calculated. The pressure range is from 0.1 to 1.2 MPa. This result is compared with those spectrums of nozzle pair with different secondary nozzle under different chamber pressures. The trend of peak frequency shifts for different nozzle pair and different chamber pressure is presented in this paper. The secondary nozzles make frequency peak shift from the source nozzle, especially in low frequency band. Different structure of secondary nozzle has different influence on the frequency characteristics of jet noise. Length of expand segment has greater influence on low frequency peak than other two factors. Joint time-frequency analysis is also used in analyze the change of frequency spectrum during throat size decreased under fixed chamber pressure and various spectrograms are also presented. In low frequency band, frequency peak remains during the change of source nozzle throat size. But in higher frequency band, the frequency peak shifts from low frequency to higher ones as the throat size decreases.

scholarly journals Frequency response and self-noise of the MET hydrophone

2018 ◽  
Vol 7 (2) ◽  
pp. 443-452 ◽  
Author(s):  
Dmitry L. Zaitsev ◽  
Svetlana Y. Avdyukhina ◽  
Maksim A. Ryzhkov ◽  
Iliya Evseev ◽  
Egor V. Egorov ◽  
...  
Keyword(s):  
Frequency Response ◽  
Experimental Model ◽  
Frequency Band ◽  
Mass Production ◽  
Low Frequency ◽  
Experimental Results ◽  
Noise Model ◽  
Frequency Range ◽  
Molecular Electronic ◽  
Methods And Techniques

Abstract. An electrochemical hydrophone based on the principles of molecular electronic transfer (MET) has been described. The paper presents theoretical and experimental results for the sensitivity and the level of self-noise determination for the MET hydrophone (METH) in the frequency range of 0.02–200 Hz, which determines the fields of acceptance of the devices being developed. An experimental model has been developed by using a force-balancing feedback. Different methods and techniques for its calibration have been developed. The experimental device with 0.75 mV Pa−1 sensitivity flat in the frequency band 0.02–200 Hz has been presented. It has been demonstrated that in the ultra-low-frequency range METH noise could be much lower than the standard Wenz noise model. Easy to produce, cheap and suitable for mass production, the MET hydrophone could be in demand in marine and land acoustic research.

A Wavelet-Based Watermarking Algorithm Using the Human Visual System

2012 ◽  
Vol 424-425 ◽  
pp. 304-308
Author(s):  
Yu Feng Chen ◽  
Gang Yin
Keyword(s):  
Visual System ◽  
Frequency Band ◽  
Human Visual System ◽  
Low Frequency ◽  
Jpeg Compression ◽  
Experimental Results ◽  
Frequency Bands

A wavelet based multiresolution watermarking method using the human visual system (HVS) is proposed. The watermark is added to the large coefficients at the middle frequency bands and low frequency band of the DWT of an image. The experimental results show that the proposed method is robust for some common image distortions, such as cutting, filtering and the JPEG compression

scholarly journals A Compact Novel Three-Port Integrated Wide and Narrow Band Antennas System for Cognitive Radio Applications

2016 ◽  
Vol 2016 ◽  
pp. 1-14 ◽  
Author(s):  
N. Anvesh Kumar ◽  
A. S. Gandhi
Keyword(s):  
Cognitive Radio ◽  
Wireless Communication ◽  
Frequency Spectrum ◽  
Spectrum Sensing ◽  
Frequency Band ◽  
Return Loss ◽  
Narrow Band ◽  
Experimental Results ◽  
Uwb Antenna ◽  
Good Agreement

The design of a three-port radiating structure, integrating wide and narrow band antennas for cognitive radio applications, is presented. It consists of a UWB antenna for spectrum sensing and two narrow band antennas for wireless communication integrated on the same substrate. The UWB antenna covers the complete UWB spectrum (3.1 GHz to 10.6 GHz) approved by FCC. In the two narrow band antennas, each antenna presents dual bands. In particular, the first narrowband antenna resonates at 6.5 GHz, covering the frequency band between 6.36 GHz and 6.63 GHz, and at 9 GHz, covering the frequency band between 8.78 GHz and 9.23 GHz, presenting minimum return loss values of 28.3 dB at 6.5 GHz and 20.5 dB at 9 GHz, respectively. Similarly, the second one resonates at 7.5 GHz, covering the frequency band between 7.33 GHz and 7.7 GHz, and at 9.5 GHz, covering the frequency band between 9.23 GHz and 9.82 GHz, presenting minimum return loss values of 19.6 dB at 7.5 GHz and 28.8 dB at 9.5 GHz, respectively. Isolation among the three antennas is less than −20 dB over the UWB frequency spectrum. These antennas are realized on a FR4 substrate of dimensions 30 mm × 30 mm × 1.6 mm. Experimental results show a good agreement between the simulated and measured results.

scholarly journals The Influence of Noise in the Super-Resolution Reconstruction of Structured Illumination Microscopy

2021 ◽  
Vol 2112 (1) ◽  
pp. 012012
Author(s):  
Jinxi Bai ◽  
Zhendong Shi ◽  
Hua Ma ◽  
Lijia Liu ◽  
Lin Zhang
Keyword(s):  
Frequency Spectrum ◽  
Low Frequency ◽  
Super Resolution ◽  
Reconstruction Method ◽  
Structured Illumination ◽  
Structured Illumination Microscopy ◽  
Frequency Information ◽  
Image Reconstruction Method ◽  
Path Structure ◽  
Influence Of Noise

Abstract As one of the mainstream super-resolution imaging technologies, structured illumination microscopy (SIM) is popular for its fast imaging speed and simple optical path structure. Spectrum separation is a key step in the reconstruction of super-resolution images. However, in the process of imaging, the unavoidable noise will seriously affect the accuracy of frequency spectrum separation. This paper carries out a simulation study on the influence of noise in the process of frequency spectrum separation. The results show that although noise can cause distortion of low-frequency information in frequency spectrum separation results, it has little influence on high-frequency information. Therefore, a super-resolution image reconstruction method is proposed to effectively suppress the influence of noise. Both simulation and experimental results are shown the method can suppress the influence of noise without losing the details of super-resolution.

Contact Current Density Analysis Inside Human Body in Low-Frequency Band Using Geometric Multi-Grid Solver

2020 ◽  
Vol E103.C (11) ◽  
pp. 588-596
Author(s):  
Masamune NOMURA ◽  
Yuki NAKAMURA ◽  
Hiroo TARAO ◽  
Amane TAKEI
Keyword(s):  
Frequency Band ◽  
Current Density ◽  
Human Body ◽  
Low Frequency ◽  
Density Analysis

scholarly journals Tunable characteristics of low-frequency bandgaps in two-dimensional multivibrator phononic crystal plates under prestrain

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Hai-Fei Zhu ◽  
Xiao-Wei Sun ◽  
Ting Song ◽  
Xiao-Dong Wen ◽  
Xi-Xuan Liu ◽  
...  
Keyword(s):  
Phononic Crystal ◽  
Real Life ◽  
Low Frequency ◽  
Acoustic Vibration ◽  
Crystal Plate ◽  
Frequency Noise ◽  
Two Dimensional ◽  
The Matrix ◽  
Noise Frequency ◽  
Realtime Control

AbstractIn view of the influence of variability of low-frequency noise frequency on noise prevention in real life, we present a novel two-dimensional tunable phononic crystal plate which is consisted of lead columns deposited in a silicone rubber plate with periodic holes and calculate its bandgap characteristics by finite element method. The low-frequency bandgap mechanism of the designed model is discussed simultaneously. Accordingly, the influence of geometric parameters of the phononic crystal plate on the bandgap characteristics is analyzed and the bandgap adjustability under prestretch strain is further studied. Results show that the new designed phononic crystal plate has lower bandgap starting frequency and wider bandwidth than the traditional single-sided structure, which is due to the coupling between the resonance mode of the scatterer and the long traveling wave in the matrix with the introduction of periodic holes. Applying prestretch strain to the matrix can realize active realtime control of low-frequency bandgap under slight deformation and broaden the low-frequency bandgap, which can be explained as the multiple bands tend to be flattened due to the localization degree of unit cell vibration increases with the rise of prestrain. The presented structure improves the realtime adjustability of sound isolation and vibration reduction frequency for phononic crystal in complex acoustic vibration environments.

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