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1993 Proceedings IEEE Ultrasonics Symposium

31 Oct-3 Nov 1993

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Displaying Results 1 - 25 of 260
  • Proceedings of IEEE Ultrasonics Symposium

    Publication Year: 1993
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (28 KB)

    The following topics were dealt with: SAW filters; SAW analysis; SAW materials; sensors; motors; acoustooptics; transducers; microscopy; nondestructive evaluation; cavitation; medical imaging; flow measurement View full abstract»

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  • Ultrasound backscatter microscope for skin imaging

    Publication Year: 1993, Page(s):985 - 988 vol.2
    Cited by:  Papers (8)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (344 KB)

    There is a growing interest in high resolution, subsurface imaging of cutaneous tissues using higher frequency ultrasound. Some of the possible applications of higher frequency skin imaging include tumour staging, boundary definition, and studies of the response of tumours to therapy, investigations of inflammatory skin conditions such as psoriasis and eczema, and basic studies of skin aging, sun ... View full abstract»

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  • A narrow transition bandwidth SAW filter using withdrawal weighting with decomposed weighting functions

    Publication Year: 1993, Page(s):1 - 4 vol.1
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (224 KB)

    Thousands of taps with small weights are required for IDTs to achieve narrow transition bandwidths in SAW filters used for satellite applications, In this paper, withdrawal weighting for IDTs is employed to eliminate diffraction problems encountered in overlap weighting. To obtain a good approximation, an original weighting function is decomposed into two functions such that the number of small we... View full abstract»

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  • Ultrasound images of the os calcis: a new method of assessment of bone status

    Publication Year: 1993, Page(s):989 - 992 vol.2
    Cited by:  Papers (9)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (356 KB)

    A complete assessment of the broadband ultrasonic attenuation (BUA) and speed of sound (SOS) distributions within the os calcis was made, using an ultrasonic mechanical scanning device with focused transducers. Measurements were performed on 12 os calces removed from fresh female cadavers. To date, we present the first parametric ultrasonic images of the os calcis. Reasonably high quality images w... View full abstract»

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  • A global optimization procedure for SPUDT filters

    Publication Year: 1993, Page(s):5 - 8 vol.1
    Cited by:  Papers (12)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (244 KB)

    Published design methods of single phase unidirectional (SPUDT) filters using internal reflections only allow for individual transducer optimization:electroacoustic transfer function (amplitude and phase), and, acoustic reflection of the loaded transducer. Consequently, multiple reflections between transducers are not taken into account for passband ripple optimization. We present a generalized me... View full abstract»

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  • Medical image enhancement using split spectrum processing

    Publication Year: 1993, Page(s):993 - 997 vol.2
    Cited by:  Papers (5)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (640 KB)

    In ultrasonic medical imaging the echoes from unwanted scatterers manifest themselves as coherent noise superimposed on tissue structure giving the image its granular appearance. In cases where the amplitude of this coherent background noise is comparable to the echo from the abnormality under investigation, ultrasonic detection and characterization of the abnormality becomes very difficult. In th... View full abstract»

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  • Synthesis and performance of medium bandwidth, low time-spurious, high out-of-band rejection SPUDT filters

    Publication Year: 1993, Page(s):9 - 13 vol.1
    Cited by:  Papers (9)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (340 KB)

    This paper discusses the synthesis and performance of a family of medium (5 to 8%) fractional bandwidth SPUDT filters for a miniature UHF SAW channelizer. These filters employ chirped input and output transducers to overcome the otherwise limited electrode reflectivity needed for the required fractional bandwidth. They are designed to achieve moderate insertion loss, low time-domain spurious, and ... View full abstract»

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  • Split spectrum processing for enhanced detection of the ultrasonic echo of a moving target in biological tissues

    Publication Year: 1993, Page(s):999 - 1003 vol.2
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (368 KB)

    This paper describes a biological application for split spectrum processing (SSP). The ultrasonic control of cryosurgery has been reported previously. It was demonstrated chat the echo of the advancing freezing front could be detected during a freeze-thaw cycle. However, the speckle noise can mask the target signal, leading to difficulties in its detection. In this study, a SSP algorithm with a mi... View full abstract»

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  • SAW devices in wireless communication systems

    Publication Year: 1993, Page(s):115 - 124 vol.1
    Cited by:  Papers (10)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (536 KB)

    This paper discusses SAW applications in wireless communication systems. Recent developments in SAW resonator technology have made it possible to design and economically manufacture devices with very low insertion losses. One-port resonators with insertion losses of 1 to 2 dB and chip sizes similar to the former higher loss units are receiving widespread acceptance in the wireless marketplace. Clo... View full abstract»

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  • Application of autoregressive spectral analysis for ultrasound attenuation: interest in highly attenuating medium

    Publication Year: 1993, Page(s):1181 - 1186 vol.2
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (396 KB)

    A second-order autoregressive (AR2) model, whose parameters are estimated with the Burg algorithm, is used to estimate the center-frequency along echo signals and its evolution versus depth. Data simulation of independent A-lines reflected by a homogeneous medium of scatterers are generated by a computer model with attenuation values ranging from 1 to 5 dB/cm MHz and an ultrasonic frequency of 5 M... View full abstract»

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  • SH-SAW taste sensor based on acoustoelectric interaction

    Publication Year: 1993, Page(s):421 - 424 vol.1
    Cited by:  Papers (7)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (256 KB)

    This paper aims at discussing an application of SH-SAW devices on 36° rotated Y cut, X-propagating LiTaO3 to a taste sensor for identifying liquid samples. Theoretical sensor sensitivity for the acoustoelectric interaction with a liquid-loading on the SAW propagation surface was derived. The results strongly suggested that by employing different center frequency SH-SAW devices, the ... View full abstract»

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  • Design methodology and synthesis techniques for ladder-type SAW resonator coupled filters

    Publication Year: 1993, Page(s):15 - 24 vol.1
    Cited by:  Papers (16)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (612 KB)

    New types of SAW filter called “extended SAW resonator coupled filter” have been developed for 800-MHz and 0.6 to 1.0 W cellular-radio pocket phones. They have not only high-performance and high-power characteristics but also very small 3rd-order nonlinearities. We investigated a new equivalent circuit for IDTs with leaky SAWs. This circuit includes propagation losses due to leakage an... View full abstract»

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  • Harmonic imaging: a model for ultrasonic speckle reduction

    Publication Year: 1993, Page(s):1005 - 1010 vol.2
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (404 KB)

    We present a speckle reduction method called Harmonic Imaging (HI). It is derived from a multi component scattering model for biological tissues. The backscattered ultrasound quadrature signal is modeled as the sum of three components after demodulation. The first component represents nonresolvable diffuse scatterers, the second subresolvable quasiperiodic scatterers, and the third resolvable quas... View full abstract»

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  • Programmable reflectors for SAW-ID-tags

    Publication Year: 1993, Page(s):125 - 130 vol.1
    Cited by:  Papers (47)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (360 KB)

    Surface acoustic wave devices for identification systems (SAW-ID-tags or SAW wireless labels) have a large potential for future applications. We concentrate in this paper on reflective SAW-ID-tags with amplitude modulation. We use splitfinger interdigital transducers as reflecting structures. If the transducers are short circuited or capacitively loaded the reflection disappears almost entirely. O... View full abstract»

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  • A new SVD-based optimal inverse filter design for ultrasonic applications

    Publication Year: 1993, Page(s):1187 - 1190 vol.2
    Cited by:  Papers (6)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (264 KB)

    A new approach for the design of optimal pseudoinverse filter for ultrasonic applications is presented. The filter is derived from the spatio-temporal impulse response of the US system at scatterer locations (assumed to be on a uniform grid) in the region of interest (ROI). We provide a derivation for the filter coefficients based linear formulation of the pulse propagation from the scatterers to ... View full abstract»

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  • Ionic solution electroacoustic transducer

    Publication Year: 1993, Page(s):435 - 438 vol.1
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (208 KB)

    An electroacoustic transducer, based on the electroacoustic effect in ionic solutions has been explored. The nonlinear performance, the possibility to model an arbitrary amplitude-frequency characteristics and the good efficiency promise practical applications as transducer, signal processor or ions sensor in solutions View full abstract»

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  • Influence of fabrication tolerances and circuit variations on the performance of SAW RF filters

    Publication Year: 1993, Page(s):257 - 261 vol.1
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (400 KB)

    By simulations based on the P-matrix model, we have studied the effects of fabrication tolerances on the performance of dual-track image impedance connected filters consisting of 6 and 22 transducers, respectively, a DMS filter, and an IIDT filter. All filters were fabricated on 36°rotY,X-LiTaO3 and operated at about 900 MHz. We have also investigated the influence of matching eleme... View full abstract»

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  • Thickness-shear and flexural vibrations of contoured crystal strip resonators

    Publication Year: 1993, Page(s):559 - 564 vol.1
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (316 KB)

    A system of two-dimensional equations of motion of successively higher-order approximations for contoured crystal plates are deduced from three-dimensional equations of elasticity by expansion in a series of trigonometrical functions. By removing the first-order thickness-stretch and x2x3 thickness-shear modes and all the higher modes, a set of first-order equations of motion... View full abstract»

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  • Ultrasonic study of mixed ferroelectrics in a DC bias field

    Publication Year: 1993, Page(s):807 - 810 vol.2
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (244 KB)

    Polarization and Raman measurements, in KTa1-XNbX O3 (KTN), have shown the existence of precursor effects many degrees above the transition. These effects are due to the formation of polar nanoregions, or clusters, which also explain the departure of the susceptibility from its Curie-Weiss dependence at high temperature. It was also shown through ultrasonic measure... View full abstract»

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  • Quartz resonators as effective detectors for dilute conductive liquids

    Publication Year: 1993, Page(s):425 - 430 vol.1
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (368 KB)

    AT-cut quartz crystal resonators (QCR) have been recently investigated as mass and viscosity detectors in liquid environments. Some experiments have also suggested that the QCR can be used to detect electrical properties of liquids. It has been pointed out by others that the absence of a surface potential on a grounded electrode will prevent such interaction which can only be due to fringing field... View full abstract»

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  • Wideband and efficient polymer transducers using multiple active piezoelectric films

    Publication Year: 1993, Page(s):757 - 760 vol.2
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (224 KB)

    Conventional ultrasound imaging transducers suffer from the trade-off between bandwidth and sensitivity, which impedes the optimization of ultrasound image quality. To alleviate this trade-off, a novel non-resonant multilayer PVDF transducer design is suggested. The design allows the overall sensitivity of the PVDF polymer transducer to be significantly improved while retaining PVDF film's wide ba... View full abstract»

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  • SPUDT/in-line coupled resonator filters

    Publication Year: 1993, Page(s):25 - 30 vol.1
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (360 KB)

    This paper presents results obtained for 71 MHz filters designed and implemented using a combination of single phase unidirectional transducers (SPUDT) and in-line coupled resonators (RFI). For simplicity the device will be referred to as a SPUDT-RFI. This approach is ideally suited for cases in which low price and small size are important considerations. A typical example is the application of th... View full abstract»

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  • Improving contrast resolution in ultrasound holographic B-imaging: comparison between simulation and experiment

    Publication Year: 1993, Page(s):1011 - 1014 vol.2
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (232 KB)

    In ultrasound holographic B-imaging data are collected coherently over a synthetic aperture using a wide insonifying beam. The method under study uses monostatic approach in data acquisition which reduces significantly the amount of data and makes it feasible for real-time applications. The monostatic approach reduces, however, the dynamical range and resolution compared to a multistatic scheme. A... View full abstract»

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  • SAW injection locked oscillators: dynamic behaviour and application to neural networks

    Publication Year: 1993, Page(s):131 - 135 vol.1
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (388 KB)

    The characteristics of an injection-locked oscillator are examined in two parts. Part A covers the dynamic behaviour of a surface acoustic wave injection-locked oscillator and its similarity near lock-in to that of an acousto-optic modulator. It is shown that a reflective wave component travels between the injected source and the oscillator resulting in periodic locking and unlocking of tile syste... View full abstract»

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  • Visual detection experiments in ultrasonography

    Publication Year: 1993, Page(s):1191 - 1194 vol.2
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (284 KB)

    The efficiencies for detecting low-contrast circular targets in acoustic speckle fields are measured for human observers. Cone-shaped targets of known contrast were scanned in cross section at 5 MHz to generate B-scan images. Target images were paired with uniform speckle fields and presented to observers who were asked to identify which of the two images contained the target. In these two-alterna... View full abstract»

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