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IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control

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https://www.readbyqxmd.com/read/28212081/a-comparative-analysis-of-cmut-receiving-architectures-for-design-optimization-of-integrated-transceiver-front-ends
#1
Marco Sautto, Alessandro Stuart Savoia, Fabio Quaglia, Giosue Caliano, Andrea Mazzanti
A formal comparison between fundamental RX amplifier configurations for Capacitive Micromachined Ultrasonic Transducers (CMUT) is proposed in this paper. The impact on both RX and the pulse-echo frequency response and on the output SNR are thoroughly analysed and discussed. It is shown that the resistive-feedback amplifier yields a band-pass RX frequency response, while both open-loop voltage and capacitivefeedback amplifiers exhibit a low-pass frequency response. For a given power dissipation, it is formally proved that a capacitivefeedback amplifier provides a remarkable SNR improvement against the commonly adopted resistive feedback stage, achieved at the expense of a reduced pulse-echo center frequency, making its use convenient in low and mid-frequency ultrasound imaging applications...
February 13, 2017: IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
https://www.readbyqxmd.com/read/28207393/optimization-of-the-close-to-carrier-phase-noise-in-a-cmos-mems-oscillator-using-a-phase-tunable-sustaining-amplifier
#2
Guillermo Sobreviela, Martin Riverola, Francesc Canals, Arantxa Del Monte, Nuria Beumala
In this paper, the phase noise of a 24-MHz CMOSMEMS oscillator with zero-level vacuum package is studied. We characterize and analyze the nonlinear regime of each one of the modules that compose the oscillator (CMOS sustaining-amplifier and MEMS resonator). As we show, the presented resonator exhibits a high nonlinear behavior. Such fact is exploited as a mechanism to stabilize the oscillation amplitude, allowing to maintain the sustaining-amplifier working in the linear regime. Consequently, the nonlinear resonator becomes the main closeto- carrier phase noise source...
February 13, 2017: IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
https://www.readbyqxmd.com/read/28207391/confidence-estimates-in-simulation-of-phase-noise-or-spectral-density
#3
Neil Ashby
In this paper we apply the method of discrete simulation of power law noise, developed in [1],[3],[4], to the problem of simulating phase noise for a combination of power law noises. We derive analytic expressions for the probability of observing a value of phase noise L(f) or of any of the onesided spectral densities S(f); Sy(f), or Sx(f), for arbitrary superpositions of power law noise.
February 13, 2017: IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
https://www.readbyqxmd.com/read/28207392/temperature-compensation-of-silicon-lam%C3%A3-resonators-using-etch-holes-theory-and-design-methodology
#4
Luca Luschi, Giuseppe Iannaccone, Francesco Pieri
We present a new approach to the temperature compensation of MEMS Lamé resonators, based on the combined effect of the doping concentration and of the geometry of etch holes on the equivalent temperature coefficients of silicon. To this purpose, we develop and validate an analytical model which describes the effect of etch holes on the temperature stability of Lamé resonators through comparison with experiments available in the literature and FEM simulations. We show that two interesting regions of the design space for Lamé resonators exist, where a cancellation of the first-order temperature coefficient of the resonance frequency is possible: [100]-oriented silicon with n-doping of 2...
February 9, 2017: IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
https://www.readbyqxmd.com/read/28186887/accelerated-singular-value-based-ultrasound-blood-flow-clutter-filtering-with-randomized-singular-value-decomposition-rsvd-and-randomized-spatial-downsampling
#5
Pengfei Song, Joshua Trzasko, Armando Manduca, Bo Qiang, Ramanathan Kadirvel, David Kallmes, Shigao Chen
Singular value decomposition (SVD)-based ultrasound blood flow clutter filters have recently demonstrated substantial improvement in clutter rejection for ultrafast plane wave microvessel imaging, and have become the commonly used clutter filtering method for many novel ultrafast imaging applications such as functional ultrasound and super-resolution imaging. At present, however, the computational burden of SVD remains as a major hurdle for practical implementation and clinical translation of this method. To address this challenge, in the study we present two blood flow clutter filtering methods based on randomized singular value decomposition (rSVD) and randomized spatial downsampling to accelerate SVD clutter filtering with minimal compromise to the clutter filter performance...
February 7, 2017: IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
https://www.readbyqxmd.com/read/28166493/a-gpu-accelerated-3d-coupled-sub-sample-estimation-algorithm-for-volumetric-breast-strain-elastography
#6
Bo Peng, Yuqi Wang, Timothy J Hall, Jingfeng Jiang
Our primary objective of this work was to extend a previously published 2D coupled sub-sample tracking algorithm for 3D speckle tracking in the framework of ultrasound breast strain elastography. In order to overcome heavy computational cost, we investigated the use of a graphic processing unit (GPU) to accelerate the 3D coupled sub-sample speckle tracking method. The performance of the proposed GPU implementation was tested using a tissue-mimicking (TM) phantom and in vivo breast ultrasound data. The performance of this 3D sub-sample tracking algorithm was compared with the conventional 3D quadratic subsample estimation algorithm...
January 31, 2017: IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
https://www.readbyqxmd.com/read/28166492/coded-excitation-for-low-snr-pulse-echo-systems
#7
Julio Isla, Frederic Cegla
Pulse compression has been used for decades in radar, sonar, medical and industrial ultrasound. It consists in transmitting a modulated and/or coded excitation, which is then cross-correlated with the received signal such that received echoes are time-compressed, thereby increasing their intensity and hence the system resolution and signal-to-noise ratio (SNR). A central problem in pulse-echo systems is that, while longer coded excitations yield higher SNRs, the length of the coded excitation or sequence is limited by the distance between the closest reflector and the transmitter/receiver...
January 30, 2017: IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
https://www.readbyqxmd.com/read/28166491/photoacoustic-ultrasound-tomography-with-s-sequence-aperture-encoding
#8
Quinn Barber, Roger J Zemp
A combined photoacoustic-ultrasound (PAUS) tomography system is introduced using a ring-array and novel aperture encoding schemes. The ultrasound sub-system is able to achieve diffraction limited half-wavelength isotropic in-plane spatial resolution unlike previous systems. S-sequence aperture encoding improves signal-to-noise ratio for the ultrasound tomography sub-system. We measured an average resolution of 139 44m for S-Sequence ultrasound tomography, and a resolution of 180 32m for photoacoustic tomography...
January 30, 2017: IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
https://www.readbyqxmd.com/read/28103552/extending-the-utility-of-the-parabolic-approximation-in-medical-ultrasound-using-wide-angle-diffraction-modeling
#9
Joshua E Soneson
Wide-angle parabolic models are commonly used in geophysics and underwater acoustics but have seen little application in medical ultrasound. Here a wide-angle model for continuous-wave high-intensity ultrasound beams is derived which approximates the diffraction process more accurately than the commonly-used Khokhlov-Zabolotskaya-Kuznetsov (KZK) equation without increasing implementation complexity or computing time. A method for preventing the high spatial frequencies often present in source boundary conditions from corrupting the solution is presented...
January 16, 2017: IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
https://www.readbyqxmd.com/read/28103551/ultrasound-flow-mapping-for-the-investigation-of-crystal-growth
#10
Norman Thieme, Paul Bonisch, Dagmar Meier, Richard Nauber, Lars Buttner, Kaspars Dadzis, Olf Patzold, Lamine Sylla, Jurgen Czarske
A high energy conversion and cost efficiency are keys for the transition to renewable energy sources, e.g. solar cells. The efficiency of multi-crystalline solar cells can be improved by enhancing the understanding of its crystallization process, especially the directional solidification. In this paper, a novel measurement system for the characterization of flow phenomena and solidification processes in low-temperature model experiments on the basis of ultrasound Doppler velocimetry is described. It captures turbulent flow phenomena in two planes with a frame rate of 3...
January 16, 2017: IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
https://www.readbyqxmd.com/read/28092534/a-k-space-pseudospectral-method-for-elastic-wave-propagation-in-heterogeneous-anisotropic-media
#11
Kamyar Firouzi, Butrus Khuri-Yakub
This paper presents the theory of the k-space method generalized to model elastic wave propagation in heterogeneous anisotropic media. The k-space methods are promising time integration techniques giving, in conjunction with collocation spectral methods, accurate and efficient numerical schemes for problems in heterogeneous media. In this study, the k-space operator is derived in a spatially continuous form using the Fourier analysis of the displacement formalism of elastodynamics. An efficient numerical algorithm is then constructed by applying a Fourier collocation spectral method, leading to define the discrete k-space scheme...
January 16, 2017: IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
https://www.readbyqxmd.com/read/28092533/linear-system-models-for-ultrasonic-imaging-intensity-signal-statistics
#12
Craig Abbey, Yang Zhu, Sara Bahramian, Michael Insana
Despite a great deal of work characterizing the statistical properties of radio-frequency backscattered ultrasound signals, less is known about the statistical properties of demodulated intensity signals. Analysis of intensity is made more difficult by a strong nonlinearity that arises in the process of demodulation. This limits our ability to characterize the spatial resolution and noise properties of B-mode ultrasound images. In this work, we generalize earlier results on two-point intensity covariance using a multivariate systems approach...
January 16, 2017: IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
https://www.readbyqxmd.com/read/28092532/improved-shear-wave-group-velocity-estimation-method-based-on-spatiotemporal-peak-and-thresholding-motion-search
#13
Carolina Amador Carrascal, Shigao Chen, Armando Manduca, James F Greenleaf, Matthew Urban
Quantitative ultrasound elastography is increasingly being used in the assessment of chronic liver disease. Many studies have reported ranges of liver shear wave velocities values for healthy individuals and patients with different stages of liver fibrosis. Nonetheless, ongoing efforts exist to stabilize quantitative ultrasound elastography measurements by assessing factors that influence tissue shear wave velocity values, such as food intake, body mass index (BMI), ultrasound scanners, scanning protocols, ultrasound image quality, etc...
January 11, 2017: IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
https://www.readbyqxmd.com/read/28092531/a-200-1380-khz-quadrifrequency-focused-ultrasound-transducer-for-neurostimulation-in-rodents-and-primates-transcranial-in-vitro-calibration-and-numerical-study-of-the-influence-of-skull-cavity
#14
Charlotte Constans, Thomas Deffieux, Pierre Pouget, Mickael Tanter, Jean-Francois Aubry
Low intensity transcranial focused ultrasound has been demonstrated to produce neuromodulation in both animals and humans. Primarily for technical reasons, frequency is one of the most poorly investigated critical wave parameters. We propose the use of a quadri-band transducer capable of operating at 200, 320, 850 and 1380 kHz for further investigation of the frequency dependence of neuromodulation efficacy while keeping the position of the transducer fixed with respect to the subject's head. This paper presents the results of the transducer calibration in water, in vitro transmission measurements through a monkey skull flap, 3D simulations based on both a μCT-scan of a rat and on CT-scans of 2 macaques...
January 11, 2017: IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
https://www.readbyqxmd.com/read/28092530/feasibility-of-multi-plane-transmit-beamforming-for-real-time-volumetric-cardiac-imaging-a-simulation-study
#15
Yinran Chen, Ling Tong, Alejandra Ortega, Jianwen Luo, Jan D'hooge
Today's three-dimensional (3-D) cardiac ultrasound imaging systems suffer from relatively low spatial and temporal resolution, limiting their applicability in daily clinical practice. To address this problem, 3-D diverging wave imaging with spatial coherent compounding (DWC) as well as 3-D multi-line-transmit (MLT) imaging have recently been proposed. Currently, the former improves the temporal resolution significantly at the expense of image quality and the risk of introducing motion artifacts whereas the latter only provides a moderate gain in volume rate but mostly preserves quality...
January 10, 2017: IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
https://www.readbyqxmd.com/read/28103194/optical-stabilization-of-a-microwave-oscillator-for-fountain-clock-interrogation
#16
Burghard Lipphardt, Vladislav Gerginov, Stefan Weyers
We describe an optical frequency stabilization scheme of a microwave oscillator that is used for the interrogation of primary caesium fountain clocks. Because of its superior phase noise properties, this scheme, which is based on an ultrastable laser and a femtosecond laser frequency comb, overcomes the frequency instability limitations of fountain clocks given by the previously utilized quartz-oscillator-based frequency synthesis. The presented scheme combines the transfer of the short-term frequency instability of an optical cavity and the long-term frequency instability of a hydrogen maser to the microwave oscillator and is designed to provide continuous long-term operation for extended measurement periods of several weeks...
January 5, 2017: IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
https://www.readbyqxmd.com/read/28060706/comparison-of-the-thermal-degradation-of-heavily-nb-doped-and-normal-pzt-thin-films
#17
Jeong-Suong Yang, Yunsung Kang, Inyoung Kang, Seungmo Lim, Seung-Joo Shin, Jungwon Lee, Kangheon Hur
The degradation of Niobium-doped lead zirconate titanate (PZT) and two types of PZT thin films were investigated. Undoped PZT, 2-step PZT and heavily Nb-doped PZT (PNZT) around the morphotropic phase boundary (MPB) were in-situ deposited under optimum condition by RF-magnetron sputtering. All 2 μm thick films had dense perovskite columnar grain structure and self-polarized (100) dominant orientation. PZT thin films were deposited on Pt/TiOx bottom electrode on Si wafer, and Nb doped PZT thin film was on Ir/TiW electrode with help of orientation control...
January 4, 2017: IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
https://www.readbyqxmd.com/read/28060705/cross-spectrum-pm-noise-measurements-thermal-energy-and-metamaterial-filters
#18
Yannick Gruson, Vincent Giordano, Ulrich L Rohde, Ajay Kumar Poddar, Enrico Rubiola
Virtually all commercial instruments for the measurement of the oscillator PM noise make use of the Cross Spectrum method (arXiv:1004.5539 [physics.ins-det], 2010). High sensitivity is achieved by correlation and averaging on two equal channels which measure the same input, and reject the background of the instrument. We show that a systematic error is always present if the thermal energy of the input power splitter is not accounted for. Such error can result in noise under estimation up to a few dB in the lowest-noise quartz oscillators, and in an invalid measurement in the case of cryogenic oscillators...
January 4, 2017: IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
https://www.readbyqxmd.com/read/28055864/a-sub-nyquist-variable-sampling-high-frequency-phased-array-beamformer
#19
Christopher A Samson, Andre Bezanson, Jeremy A Brown
A digital receive beamformer implementing a 'one sample per pixel' variable sampling technique is described. The sampling method reduces the required sampling rates by a factor of 3, and reduces the data capture rate by a factor of 2, in comparison to previous systems based on variable sampling. The sampling method is capable of estimating broadband pulse envelopes accurate for bandwidths up to 83.0%. This beamforming method has been implemented on an FPGA with maximum transmit and receive delay errors measured to be less than ± 1...
December 30, 2016: IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
https://www.readbyqxmd.com/read/28029621/drifts-and-environmental-disturbances-in-atomic-clock-subsystems-quantifying-local-oscillator-control-loop-ion-resonance-interactions
#20
Daphna G Enzer, William A Diener, David W Murphy, Shanti R Rao, Robert L Tjoelker
Linear ion trap frequency standards are among the most stable continuously-operating frequency references and clocks. Depending on the application, they have been operated with a variety of Local Oscillators (LO) including quartz Ultra-Stable Oscillators (USO), Hydrogen-masers, and Cryogenic Sapphire Oscillators. The short, intermediate, and long term stability of the frequency output is a complicated function of the fundamental performances, the time dependence of environmental disturbances, the atomic interrogation algorithm, the implemented control loop, and the environmental sensitivity of the LO and atomic system components...
December 19, 2016: IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
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