3,729 research outputs found
A study of high-speed AD and DA converters using redundancy techniques Interim report, May 10, 1963 - May 9, 1964
High speed analog-to-digital converters compared using redundancy encoding technique
Phase detector assembly Patent
Detector assembly for discriminating first signal with respect to presence or absence of second signal at time of occurrence of first signa
An Experiment and Detection Scheme for Cavity-based Cold Dark Matter Searches
A resonance detection scheme and some useful ideas for cavity-based searches
of light cold dark matter particles (such as axions) are presented, as an
effort to aid in the on-going endeavors in this direction as well as for future
experiments, especially in possibly developing a table-top experiment. The
scheme is based on our idea of a resonant detector, incorporating an integrated
Tunnel Diode (TD) and a GaAs HEMT/HFET (High Electron Mobility
Transistor/Heterogenous FET) transistor amplifier, weakly coupled to a cavity
in a strong transverse magnetic field. The TD-amplifier combination is
suggested as a sensitive and simple technique to facilitate resonance detection
within the cavity while maintaining excellent noise performance, whereas our
proposed Halbach magnet array could serve as a low-noise and permanent solution
replacing the conventional electromagnets scheme. We present some preliminary
test results which demonstrate resonance detection from simulated test signals
in a small optimal axion mass range with superior Signal-to-Noise Ratios (SNR).
Our suggested design also contains an overview of a simpler on-resonance dc
signal read-out scheme replacing the complicated heterodyne readout. We believe
that all these factors and our propositions could possibly improve or at least
simplify the resonance detection and read-out in cavity-based DM particle
detection searches (and other spectroscopy applications) and reduce the
complications (and associated costs), in addition to reducing the
electromagnetic interference and background.Comment: 22 pages, 7 figure
The integration of Si-based resonant interband
eports the first demonstration of the integration of CMOS and Si/SiGe resonant interband tunnel diode (RITD). In Si-based material, recent breakthrough in Si/SiGe RITD grown using molecular beam epitaxy (MBE) made the integration with CMOS possible. The resultant devices enabled the realization of RITD CMOS circuitry, and a NMOS-RITD MOBILE latch was demonstrated in Si, all enabling digital and ternary circuit design for density storag
A miniature electromechanical tunnel diode transducer
Miniature electromechanical tunnel diode transduce
A prototype station for ARIANNA: a detector for cosmic neutrinos
The Antarctic Ross Iceshelf Antenna Neutrino Array (ARIANNA) is a proposed
detector for ultra-high energy astrophysical neutrinos. It will detect coherent
radio Cherenkov emission from the particle showers produced by neutrinos with
energies above about 10^17 eV. ARIANNA will be built on the Ross Ice Shelf just
off the coast of Antarctica, where it will eventually cover about 900 km^2 in
surface area. There, the ice-water interface below the shelf reflects radio
waves, giving ARIANNA sensitivity to downward going neutrinos and improving its
sensitivity to horizontally incident neutrinos. ARIANNA detector stations will
each contain 4-8 antennas which search for brief pulses of 50 MHz to 1 GHz
radio emission from neutrino interactions.
We describe a prototype station for ARIANNA which was deployed in Moore's Bay
on the Ross Ice Shelf in December 2009, discuss the design and deployment, and
present some initial figures on performance. The ice shelf thickness was
measured to be 572 +/- 6 m at the deployment site.Comment: 15 pages with 5 figure
A battery-less, self-sustaining RF energy harvesting circuit with TFETs for µW power applications
This paper proposes a Tunnel FET (TFET) power management circuit for RF energy harvesting applications. In contrast with conventional MOSFET technologies, the improved electrical characteristics of TFETs promise a better behavior in the process of rectification and conversion at ultra-low power (µW) and voltage (sub-0.25 V) levels. RF powered systems can not only benefit from TFETs in front-end rectifiers by harvesting the surrounding energy at levels where conventional technologies cannot operate but also in the minimization of energy required by the power management circuit. In this work we present an energy harvesting circuit for RF sources designed with TFETs. The TFET controller emulates an adequate impedance at the output of the rectifier in order to allow maximum transfer of power from the RF source to the input of the boost converter. The output load is activated once the output capacitor reaches a voltage value of 0.5 V. The results show an efficiency boost of 89 % for an output load consuming 1 µW with an available RF power of -25 dBm.Postprint (published version
Index to nasa tech briefs, issue number 2
Annotated bibliography on technological innovations in NASA space program
Insights into tunnel FET-based charge pumps and rectifiers for energy harvesting applications
In this paper, the electrical characteristics of tunnel field-effect transistor (TFET) devices are explored for energy harvesting front-end circuits with ultralow power consumption. Compared with conventional thermionic technologies, the improved electrical characteristics of TFET devices are expected to increase the power conversion efficiency of front-end charge pumps and rectifiers powered at sub-µW power levels. However, under reverse bias conditions the TFET device presents particular electrical characteristics due to its different carrier injection mechanism. In this paper, it is shown that reverse losses in TFET-based circuits can be attenuated by changing the gate-to-source voltage of reverse-biased TFETs. Therefore, in order to take full advantage of the TFETs in front-end energy harvesting circuits, different circuit approaches are required. In this paper, we propose and discuss different topologies for TFET-based charge pumps and rectifiers for energy harvesting applications.Peer ReviewedPostprint (author's final draft
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