Levent Degertekin

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A miniature differential microphone is described having a low-noise floor. The sensitivity of a differential microphone suffers as the distance between the two pressure sensing locations decreases, resulting in an increase in the input sound pressure-referred noise floor. In the microphone described here, both the diaphragm thermal noise and the electronic(More)
This paper describes a low-power approach to capacitive sensing that achieves a high signal-to-noise ratio. The circuit is composed of a capacitive feedback charge amplifier and a charge adaptation circuit. Without the adaptation circuit, the charge amplifier only consumes 1 μW to achieve the audio band SNR of 69.34dB. An adaptation scheme using(More)
  • A G Onaran, M Balantekin, W Lee, G W Woodruff, W L Hughes, B A Buchine +4 others
  • 2006
We introduce a novel probe structure for the atomic force microscope. The probe has a sharp tip placed on a micromachined membrane with an integrated displacement sensor, a diffraction-based optical interferometer. We use this probe in a microscope to directly measure the transient interaction forces between the probe tip and the sample when operating in a(More)
  • F L Degertekin, A G Onaran, M Balantekin, W Lee, G W Woodruff, N A Hall +1 other
  • 2005
We introduce a sensor for direct measurement of tip-sample interaction forces in probe microscopy. The sensor uses a micromachined membrane structure built on a transparent substrate with an integrated diffraction grating for optical interferometric detection, and a built-in electrostatic actuator. To demonstrate our concept for this sensor, we measured the(More)
We designed and fabricated a dynamic receive beamformer integrated circuit (IC) in 0.35-μm CMOS technology. This beamformer IC is suitable for integration with an annular array transducer for high-frequency (30-50 MHz) intravascular ultrasound (IVUS) imaging. The beamformer IC consists of receive preamplifiers, an analog dynamic delay-and-sum beamformer,(More)
An actuation method for atomic force microscope ͑AFM͒ cantilevers in fluids is reported. The radiation pressure generated by a focused acoustic transducer at radio frequency ͑rf͒ ͑100–300 MHz͒ exerts a localized force of controlled amplitude at a desired location on the AFM cantilever. This force can be used to measure the spring constant and other dynamic(More)
In this paper, the flrst experimental results of pulse-echo imaging employing a 1-D capacitive microma-chined ultrasonic transducer array are presented. A 1-D array consisting of 16 elements is used in the experiment. A wire phantom consisting of seven steel wires immersed in vegetable oil is used as the imaging target. A B-scan image with a sector angle of(More)
The authors describe a method of actuation for atomic force microscope (AFM) probes to improve imaging speed and displacement range simultaneously. Unlike conventional piezoelectric tube actuation, the proposed method involves a lever and fulcrum "seesaw" like actuation mechanism that uses a small, fast piezoelectric transducer. The lever arm of the seesaw(More)