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Frequency Conversion (frequency + conversion)

Distribution by Scientific Domains

Engineering	50%

Selected Abstracts

Low-frequency noise conversion modeling in RF devices under forced nonlinear operation

INTERNATIONAL JOURNAL OF RF AND MICROWAVE COMPUTER-AIDED ENGINEERING, Issue 1 2006
Gabriele Conte
Abstract The article addresses the frequency conversion of low-frequency noise deriving from trap-assisted generation-recombination (GR) noise in RF devices under forced, nonlinear operation through a physics-based noise model. The superposition of the stationary (small-signal) GR spectra originating from noninteracting trap levels with properly distributed energies is shown, in simple yet significant device case studies, to yield a 1/f or 1/f -like behaviour over a prescribed frequency range. The same trap distribution is also exploited for large-signal, cyclostationary noise simulation in forced periodic conditions. In this case, low-frequency 1/f -like noise is shown to be upconverted from the baseband to all noise sidebands. Circuit-level compact modeling strategies for noise-frequency conversion based on the modulation of small-signal low-frequency noise are also investigated and compared to the fundamental approach. © 2005 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2006. [source]

Microstructure-fiber frequency converters

LASER PHYSICS LETTERS, Issue 5 2004
A. M. Zheltikov
Abstract Microstructure fibers with multiple micron and submicron fused silica waveguide channels are shown to be ideally suited for highly efficient anti-Stokes frequency conversion. These fibers are capable of generating ultrashort pulses of frequency-tunable radiation with controlled chirp, allowing the creation of new sources of tunable radiation for applications in spectroscopy, photochemistry, optical metrology, photobiology, and biomedicine. (© 2004 by ASTRO, Ltd. Published exclusively by WILEY-VCH Verlag GmbH & Co. KGaA) [source]

Diode pumped 500-picosecond Nd:GdVO4 Raman laser

LASER PHYSICS LETTERS, Issue 5 2004
T. T. Basiev
Abstract Self-Raman frequency conversion in a diode-pumped passively Q-switched Nd:GdVO4 laser has been demonstrated. The use of LiF:F,2 crystal as a saturable absorber has provided effective Q-switching of the Nd:GdVO4 laser with high pulse energy. The laser pulse duration at the 1st Stokes wavelength 1174 nm was as short as 500 ps. Diode-to-Raman optical conversion efficiency more than 2 % at the pulse peak power of 9 kW was achieved. (© 2004 by ASTRO, Ltd. Published exclusively by WILEY-VCH Verlag GmbH & Co. KGaA) [source]

Cancellation of local oscillator phase-noise in 60-GHz high-data-rate wireless systems

MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 4 2004
C. Loyez
Abstract A cancellation device of phase-noise is implemented in a wireless system at 60 GHz. By using only MMIC VCOs to perform frequency conversions, such a system effectively transmits signals with a QPSK-modulation scheme. For a 50 Mb/s data-rate, performances are similar to that of an ideal conventional system. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 42: 268,272, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20274 [source]