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For phased-array ultrasound imaging, alternative beamforming techniques and their VLSI circuits are studied to form a fully digital receive front-end hardware. In order to increase the timing accuracy in beamforming, a computationally efficient interpolation scheme to increase the sampling rate is examined. For adaptive beamforming, a phase aberration(More)
The current state of novel technology, surface microfabricated ultrasonic transducers, is reported. Experiments demonstrating both air and water transmission are presented. Air-coupled longitudinal wave transmission through aluminum is demonstrated, implying a 110 dB dynamic range for transducers at 2.3 MHz in air. Water transmission experiments from 1 to(More)
Abstruct-A new method is proposed for dominant pole-zero (or pole-residue) analysis of large linear microwave circuits containing both lumped and distributed elements. The method is based on a multipoint Pad6 approximation. It finds a reduced-order rational s-domain transfer function using a data set obtained by solving the circuit at only a few frequency(More)
—An evolutionary algorithm is used to find three sets of binary sequences of length 49–100 suitable for the synchronization of digital communication systems. Optimization of the sets are done by taking into consideration the type of preamble used in data frames and the phase-lock mechanism of the communication system. The preamble is assumed to be either a(More)
A computationally efficient method for phase aberration correction in ultrasound imaging is presented. The method is based on time delay estimation via minimization of the sum of absolute differences between radio frequency samples of adjacent array elements. Effects of averaging estimated aberration patterns over scan angle and truncation to a single bit(More)
Recent advances now permit the use of scanning acoustic microscopy for the analysis of subcellular components. By sequential viewing of identified fixed cells with acoustic, light, and electron microscopy, we have established that the acoustic microscope can readily detect such features as nuclei and nucleoli, mitochondria, and actin cables. Under optimal(More)
Orthogonal frequency division multiplexing (OFDM) is a data transmission technique which is used in wired and wireless digital communication systems. In this technique, fast Fourier transformation (FFT) and inverse FFT (IFFT) are kernel processing blocks in an OFDM system, and are used for data (de)modulation. OFDM systems are increasingly required to be(More)
Capacitive micromachined ultrasonic transducers (cMUT) have large bandwidths, but they typically have low conversion efficiencies. This paper defines a performance measure in the form of a gain-bandwidth product and investigates the conditions in which this performance measure is maximized. A Mason model corrected with finite-element simulations is used for(More)
Bias controlled capacitive driven cantilever oscillation for high resolution dynamic force microscopy Appl. A correlation force spectrometer for single molecule measurements under tensile load Compact metal probes: A solution for atomic force microscopy based tip-enhanced Raman spectroscopy Rev. Note: Radiofrequency scanning probe microscopy using(More)
Ž. High-density through-wafer interconnects are incorporated in a two-dimensional 2D micromachined cantilever array. The design addresses alignment and density issues associated with 2D arrays. Each cantilever has piezoresistive deflection sensors and high-aspect ratio silicon tips. The fabrication process and array operation are described. The integration(More)