Superconducting bandpass ΔΣ modulator with 2.23-GHz center frequency and 42.6-GHz sampling rate

2002 ◽  
Vol 37 (12) ◽  
pp. 1695-1702 ◽  
Author(s):  
J.F. Bulzacchelli ◽  
Hae-Seung Lee ◽  
J.A. Misewich ◽  
M.B. Ketchen
Keyword(s):  
Sampling Rate ◽  
Center Frequency

A Combined Interpolation Method for Cross Correlation Based Particle Velocity Measurement

2012 ◽  
Vol 508 ◽  
pp. 67-70
Author(s):  
Gang Yang ◽  
Wei Dong Li ◽  
Yu Tao Wang ◽  
Ming Yu Li
Keyword(s):  
Correlation Function ◽  
Velocity Measurement ◽  
Cross Correlation ◽  
Interpolation Method ◽  
Sampling Rate ◽  
Time Delay Estimation ◽  
Parametric Models ◽  
Center Frequency ◽  
Estimation Accuracy ◽  
Particulate Solids

Cross correlation techniques have been proved to be a valuable tool for online continuous velocity measurement of particulate solids in pneumatic pipelines. In order to reduce computational complexity the sampling frequency is usually kept as low as possible, and the peak in the correlation function is found by interpolating the correlation function. Parabola functions are commonly used as parametric models of the cross correlation function in time delay estimation. However, the parabolic-fit interpolation method introduces a bias at low sampling rate to the center frequency ratio of input signal. In this paper, a combined interpolation method is proposed to improve the estimation accuracy. Experiments are carried out to evaluate the performance of the proposed interpolation method for low sampling rate. The experimental results have been promising and have shown the potential of the proposed method for particle flow velocity measurements.

scholarly journals Burial Depth Effect of Crack on the Lcr Wave Acoustoelastic Coefficient for Stress Measurement of Laser Cladding Coating

Materials ◽  
2020 ◽  
Vol 13 (12) ◽  
pp. 2823
Author(s):  
Bin Liu ◽  
Zhihao Zeng ◽  
Jiayang Gu ◽  
Shujin Chen ◽  
Peng He ◽  
...  
Keyword(s):  
Wavelet Analysis ◽  
Laser Cladding ◽  
Stress Measurement ◽  
Sampling Rate ◽  
Tensile Load ◽  
Experimental Results ◽  
Center Frequency ◽  
Burial Depth ◽  
Depth Effect ◽  
Acoustoelastic Effect

In this paper, the influence of burial depth of crack on stress measurement of laser cladding coating with the critical refracted longitudinal wave (Lcr wave) was discussed based on the Lcr wave acoustoelastic effect. The regular rectangular slots with different depths that were used to simulate the burial crack in coating was based on the equivalent theory. The experimental system including an ultrasonic wave generator, digital oscilloscope (2.5 GHz sampling rate), and two Lcr wave transducers (2.5 MHz center frequency) was used to collect the Lcr wave under different tensile loads, and the Lcr wave was denoised by using wavelet analysis technology, then the fracture morphology was observed using SEM. The results show that after the denoising by wavelet analysis technology, the signal-to-noise ratio of Lcr wave becomes bigger and the mean square deviation of Lcr wave becomes smaller. When the tensile load is within the turning point load, the difference in time of flight between Lcr wave increases linearly as the tensile load increases, and the deviation of the experimental results becomes obvious as the tensile load increases. When the tensile load is the same, as the burial depth of the slot increases, the nominal Lcr wave acoustoelastic coefficient decreases and tends to be stable gradually. At last, the experimental results are discussed based on the Lcr wave acoustoelastic effect and deformation theory, and it is analyzed that the uneven deformation caused by the interface in coating, anisotropic microstructure, and the burial crack is considered as the main reason.

The extended Fourier algorithm: Application in discrete optics and electron holography

1994 ◽  
Vol 52 ◽  
pp. 918-919
Author(s):  
E. Voelkl ◽  
L. F. Allard
Keyword(s):  
Fourier Transform ◽  
Fourier Transforms ◽  
Sampling Rate ◽  
Electron Holography ◽  
Optical Bench ◽  
Fourier Space ◽  
Ccd Cameras ◽  
Simulated Image ◽  
Initial Sampling ◽  
Fourier Algorithm

The conventional discrete Fourier transform can be extended to a discrete Extended Fourier transform (EFT). The EFT allows to work with discrete data in close analogy to the optical bench, where continuous data are processed. The EFT includes a capability to increase or decrease the resolution in Fourier space (thus the argument that CCD cameras with a higher number of pixels to increase the resolution in Fourier space is no longer valid). Fourier transforms may also be shifted with arbitrary increments, which is important in electron holography. Still, the analogy between the optical bench and discrete optics on a computer is limited by the Nyquist limit. In this abstract we discuss the capability with the EFT to change the initial sampling rate si of a recorded or simulated image to any other(final) sampling rate sf.

The Attenuation of Very Low Frequency Brain Oscillations in Transitions from a Rest State to Active Attention

2009 ◽  
Vol 23 (4) ◽  
pp. 191-198 ◽  
Author(s):  
Suzannah K. Helps ◽  
Samantha J. Broyd ◽  
Christopher J. James ◽  
Anke Karl ◽  
Edmund J. S. Sonuga-Barke
Keyword(s):  
Brain Activity ◽  
Sampling Rate ◽  
Low Frequency ◽  
Future Research ◽  
Adhd Symptoms ◽  
Default Mode ◽  
Very Low Frequency ◽  
Wide Range ◽  
Interference Hypothesis ◽  
Mode Interference

Background: The default mode interference hypothesis ( Sonuga-Barke & Castellanos, 2007 ) predicts (1) the attenuation of very low frequency oscillations (VLFO; e.g., .05 Hz) in brain activity within the default mode network during the transition from rest to task, and (2) that failures to attenuate in this way will lead to an increased likelihood of periodic attention lapses that are synchronized to the VLFO pattern. Here, we tested these predictions using DC-EEG recordings within and outside of a previously identified network of electrode locations hypothesized to reflect DMN activity (i.e., S3 network; Helps et al., 2008 ). Method: 24 young adults (mean age 22.3 years; 8 male), sampled to include a wide range of ADHD symptoms, took part in a study of rest to task transitions. Two conditions were compared: 5 min of rest (eyes open) and a 10-min simple 2-choice RT task with a relatively high sampling rate (ISI 1 s). DC-EEG was recorded during both conditions, and the low-frequency spectrum was decomposed and measures of the power within specific bands extracted. Results: Shift from rest to task led to an attenuation of VLFO activity within the S3 network which was inversely associated with ADHD symptoms. RT during task also showed a VLFO signature. During task there was a small but significant degree of synchronization between EEG and RT in the VLFO band. Attenuators showed a lower degree of synchrony than nonattenuators. Discussion: The results provide some initial EEG-based support for the default mode interference hypothesis and suggest that failure to attenuate VLFO in the S3 network is associated with higher synchrony between low-frequency brain activity and RT fluctuations during a simple RT task. Although significant, the effects were small and future research should employ tasks with a higher sampling rate to increase the possibility of extracting robust and stable signals.

Quantitative evaluation of slow fluctuations of the volume of liquids inside cranial cavity

2019 ◽  
pp. 51-63 ◽  
Author(s):  
Yu. E. Moskalenko ◽  
T. I. Kravchenko ◽  
Yu. V. Novozhilova
Keyword(s):  
Brain Activity ◽  
Sampling Rate ◽  
Age Groups ◽  
Pulse Amplitude ◽  
Cranial Cavity ◽  
Current Frequency ◽  
Physiological Indicators ◽  
Physiological Phenomenon ◽  
Long Time ◽  
Manned Space

Introduction. Slow fl uctuations in the volume and pressure of liquids in the cranial cavity have been known for a long time and have been studied for more than 100 years. However, their quantitative indicators and their practical signifi cance remain unclear until now due to the diffi culties of research. Nevertheless, it was found that they were connected with the brain activity, which made it possible to use them as one of the physiological indicators in studying the problems of manned space fl ights. Goal of research — to study the possibility of using spectral analysis of slow fl uctuations of the volume of liquids inside the cranium in order to realize the quantitative assessment of their indicators with the use of modern microelectronics and computer technology.Materials and methods. In order to solve this problem we created a complex, in which rheoencephalograph-RG-01 («Mizar») was used as a converter-modulator of physiological signals into electrical oscillations. The device was connected with the ADC (Firm «ADIstrument»), Its software allows to calculate the spectrogram with a sampling rate of 128 kHz. Studies were conducted on volunteers of younger, middle and older age groups. The respiratory rate and the electrocardiography were registered together with the rheoencephalography. Electrodes were fi xed on the volonteers′ fronto-mastoid area.Results. Slow fl uctuations the cranium representan independent physiological phenomenon. The most considerable and valuable were fl uctuations in 0,1–0,3 Hz. It was found that current frequency of 100 or 200 kHz and frequency for quantization of 80–100 kHz was optimal for performing their spectrograms. The structure of such diagram consists of 4–7 peaks with amplitude of 0,4–0,7 units compared with REG pulse amplitude. They depend on age and are characterized by hemispheric asymmetry. Spectral diagrams of slow fl ucation inside cranium are representing inpendent physiological phenomenon. These fl uctuations are not connected by common origin, with heart activity and respiration. They are connected by nature with brain activity and PRM.Conclusion. Can be an informative method for diagnostic and assessment of general status of osteopathic patients well as for the assessment of mechanisms of action of some osteopathic techniques.

Power Efficient Implementation of Low Noise CMOS LC VCO using 32nm Technology for RF Applications

2018 ◽  
Vol 6 (8) ◽  
pp. 53
Author(s):  
Shitesh Tiwari ◽  
Sumant Katiyal ◽  
Parag Parandkar
Keyword(s):  
Power Consumption ◽  
Phase Noise ◽  
Tuning Range ◽  
Low Voltage ◽  
Performance Comparison ◽  
Low Noise ◽  
Center Frequency ◽  
Voltage Controlled Oscillator ◽  
Low Phase Noise ◽  
Lc Vco

Voltage Controlled Oscillator (VCO) is an integral component of most of the receivers such as GSM, GPS etc. As name indicates, oscillation is controlled by varying the voltage at the capacitor of LC tank. By varying the voltage, VCO can generate variable frequency of oscillation. Different VCO Parameters are contrasted on the basis of phase noise, tuning range, power consumption and FOM. Out of these phase noise is dependent on quality factor, power consumption, oscillation frequency and current. So, design of LC VCO at low power, low phase noise can be obtained with low bias current at low voltage.  Nanosize transistors are also contributes towards low phase noise. This paper demonstrates the design of low phase noise LC VCO with 4.89 GHz tuning range from 7.33-11.22 GHz with center frequency at 7 GHz. The design uses 32nm technology with tuning voltage of 0-1.2 V. A very effective Phase noise of -114 dBc / Hz is obtained with FOM of -181 dBc/Hz. The proposed work has been compared with five peer LC VCO designs working at higher feature sizes and outcome of this performance comparison dictates that the proposed work working at better 32 nm technology outperformed amongst others in terms of achieving low Tuning voltage and moderate FoM, overshadowed by a little expense of power dissipation. 

Sign in / Sign up

Export Citation Format

Share Document