Search results for "Signal"
showing 10 items of 6924 documents
Design scheme for Mach–Zehnder interferometric coarse wavelength division multiplexing splitters and combiners
2006
I propose an analytical approach to design flattened wavelength splitters with cascaded Mach–Zehnder inter- ferometers when wavelength dependence of the directional couplers cannot be neglected. I start from a geo- metrical representation of the action of a doubly point-symmetrical filter, assuming no wavelength dependence of the couplers. Next I derive the analytical formulas behind its working principle and extend them to the wavelength-dependent case. I also show how the geometrical representation allows one to broaden the class of working structures. © 2006 Optical Society of America
Design of an integrated low-noise, low-power charge sensitive preamplifier for γ and particle spectroscopy with solid state detectors
2014
The design of an integrated charge-sensitive preamplifier suitable for γ-ray spectroscopy is presented. It is fully integrated, except for the feedback resistor, and can drive directly a 50Ω cable with its low impedance output stage. It is designed in AMS 0.35µm technology and its small dimensions and low power consumption (10 mW) are optimized for multi-channel applications. It works both with germanium and silicon detectors for a large range of values of electrode and feedback capacitances. Its wide bandwidth ensures a risetime of 10 ns or less in most configurations. This characteristic makes the preamplifier suitable not only for high resolution spectroscopy but also for pulse-shape ana…
Digitaler Spektrumstabilisator für schnelle Analog-Digital-Konverter
1969
Abstract A versatile spectrum stabilizer is described, suitable for all ADC's with a digital parallel output and a pilot pulse at the end of the conversion. The stabilizer is especially developed for a 100 MHz ADC, but it is independent of the digitizing rate and the mode of conversion. The unit has a maximum cyclus time of 2 μsec and permits a parallel transfer rate of 500 kHz. The stabilizer corrects the effects of gain drift and is insensitive to statistical errors.
Ultra-broadband terahertz time domain spectroscopy by Solid State Biased Coherent Detection
2017
The spectral fingerprint of ibuprofen within the THz frequency window has been retrieved through an ultra-broadband THz Time Domain Spectrometry set-up. The latter implements the Solid State Biased Coherent Detection scheme, based on a compact CMOS-compatible integrated device. Such a technique shows unprecedented advantages in term of bandwidth (greater than 10 THz) over other solid state methods like electro-optic sampling.
X-wave bullets with negative group velocity in vacuum.
2006
Propagation-invariant, X waves with negative group velocity are reported. Beam aperturing allows for a comprehensive analysis concerning the causality of the optical signal and forerunner formation.
The filter wheel and filters development for the X-IFU instruments onboard Athena
2016
Athena is the large mission selected by ESA in 2013 to investigate the science theme “Hot and Energetic Universe” and presently scheduled for launch in 2028. One of the two instruments located at the focus of the 12 m-long Athena telescope is the X-ray Integral Field Unit (X-IFU). This is an array of TES microcalorimeters that will be operated at temperatures of 50 mK in order to perform high resolution spectroscopy with an energy resolution down to 2.5 eV at energies < 7 keV. In order to cope with the large dynamical range of X-ray fluxes spanned by the celestial objects Athena will be observing, the X-IFU will be equipped with a filter wheel. This will allow the user to fine tune the i…
Realization of a robust single-parameter quantized charge pump
2008
This paper describes a novel scheme for quantized charge pumping based on single-parameter modulation. The device is realized in an AlGaAs-GaAs gated nanowire. A particular advantage of this realization is that operation in the quantized regime can be achieved in a potentially large range of amplitude and dc off-set of the driving signal. This feature together with the simple configuration might enable large scale parallel operation of many such devices.
How does environmental variation translate into biological processes?
2001
Birth and death rates, as so many other biological processes, are usually not linearly related to environmental variation. Common examples of non-linear response forms include unimodal ‘‘optimum-type’’ responses and various saturating responses. These responses filter the signal coming from the environment to a corresponding biological process. We explored how different types of environmental signal may be transformed to a biological process. We were interested in the effect of the filter on modulation of (1) the variance of the signal, on (2) the variance-covariance structure between the signal and the filtered signal, and on (3) the match between the power spectra of the signal and the fi…
Charge Form Factor of the Neutron at Low Momentum Transfer from theH→2(e→,e′n)H1Reaction
2008
We report new measurements of the neutron charge form factor at low momentum transfer using quasielastic electrodisintegration of the deuteron. Longitudinally polarized electrons at an energy of 850 MeV were scattered from an isotopically pure, highly polarized deuterium gas target. The scattered electrons and coincident neutrons were measured by the Bates Large Acceptance Spectrometer Toroid (BLAST) detector. The neutron form factor ratio ${G}_{E}^{n}/{G}_{M}^{n}$ was extracted from the beam-target vector asymmetry ${A}_{\mathrm{ed}}^{V}$ at four-momentum transfers ${Q}^{2}=0.14$, 0.20, 0.29, and $0.42\text{ }\text{ }(\mathrm{GeV}/c{)}^{2}$.
SU-E-T-237: Monte Carlo Dosimetric Characterization of the Mobetron Mobile Linac
2014
Purpose: The aim of this work is to characterize dosimetrically a clinical intraoperative electron beam accelerator, Mobetron (IntraOp Medical, Inc.) in clinical use in our Hospital. Once this first step is completed our purpose is to evaluate shielding requirements for such a device by preparing adequate phase space files. Methods: It is known that electron beam simulation parameters required for state-of-the-art Monte Carlo codes to obtain a good match with measured data, like the mean energy or the FWHM, may not be code-independent due to the different set of process simulated and formalisms involved. Then, to cross-check our results against any issue in the simulation we have compared e…