3,854 research outputs found
Characterization of the effects of CW and pulse CW interference on the GPS signal quality
No full textIn the Global Positioning System (GPS), code division multiple access (CDMA) signals are used. Because of the spectral characteristics of the CDMA signal, each particular type of interference (signals to be rejected) has a different effect on the quality of the received GPS satellite signals. In this paper, the effects of three types of interference are studied on the carrier-to-noise ratio (C/N0) of the received GPS signal as an indicator of the quality of that signal; continuous wave (CW) and pulse CW. For CW interference, it is analytically shown that the C/N0 of the signal can be calculated using a closed formula after the correlator in the receiver. This result is supported by calculating the C/N0 using the I and Q data from a software GPS receiver. For pulsed CW, a similar analysis is performed to characterize the effect of parameters such as pulse repetition period (PRP) and also duty cycle on the received signal quality. It is specifically shown that for equal interference power levels, in the cases where the PRP is far less than the pseudorandom noise code period, the signal degradation increases with increasing the duty cycle whereas it doesn't change when the two periods are equal or the PRP is far bigger than the code perio
Cw ion lasers pumped by electron beams
Get PDFWe have obtained cw laser radiation from singly ionized Hg, I, Cd, Se, and As by exciting He metal-vapor mixtures with a dc electron beam. The beam is generated by glow discharge electron guns located apart from the active medium. This is the first time that cw ion laser action has been obtained using electron beam excitation
CW laser action in atomic fluorine
Get PDFWe have obtained CW laser action on four transitions in the doublet system of atomic fluorine for the first time. All previously reported laser action was on a pulsed basis only. CW laser radiation was obtained when F2 or AgF was used as a fluorine donor in an electron beam pumped helium plasma. A multiline output power of 200 mW was obtained
CW silver ion laser with electron beam excitation
Get PDFA CW laser power of 140 mW was obtained in the 840.39 nm transition of Ag II by electron beam excitation. This electron beam excited metal vapor ion laser is capable of operating using metals with high vaporization temperatures and is of interest for generation of CW coherent radiation in the 220-260 nm spectral region
1-W cw Zn ion laser
Get PDFWe have obtained 1.2W of cw laser power on the 4911.6- and 4924.0-Å transitions of Zn II by exciting a He-Zn gas mixture with a dc glow discharge electron beam. In addition, 0.25-W output power has been obtained on the 6149.9-Å line of Hg+ using the same excitation scheme. The combination of electron beam ionization of rare gas atoms and subsequent charge transfer excitation to metal ion levels is shown to have the potential of significantly increasing the efficiency of ion lasers. cw multiwatt visible and ultraviolet ion lasers operating at efficiencies > 10-3 appear feasible using this excitation scheme
Stabilization as a CW approximation
No full textAbstractThis paper describes a peculiar property of the category of S-modules constructed by the author, Kriz, Mandell, and May: the full subcategory of suspension spectra (all of which are S-modules) forms a precise copy of the category of topological spaces. Consequently, the “classical” homotopy category of S-modules with morphisms the actual homotopy classes of maps contains a copy of unstable homotopy theory. Stabilization and stable homotopy are induced by CW approximation as S-modules. One consequence is that CW complexes whose suspension spectra are CW S-modules must be contractible
Cw iodine ion laser excited by an electron beam
Get PDFCW laser oscillation has been obtained on the 5760.7 and6127.5 Å transitions of singly ionized iodine in an He-I2 plasma excited by a dc electron beam
A closed manifold is a fat CW complex
Get PDFIn this paper, we introduce a notion of a fat CW complex to show that a
closed manifold is a regular CW complex, while it is not always the case if we
discuss about a smooth CW structure, introduced by the first author, instead of
a fat CW structure. We also verify that de Rham theorem holds for a fat CW
complex and that a regular CW complex is reflexive in the sense of Y.~Karshon,
J.~Watts and P.~I-Zemmour. Further, any topological CW complex is topologically
homotopy equivalent to a fat CW complex. It implies that there are lots of
non-manifold examples supporting de Rham theorem.Comment: 17 page
Electron beam pumped cw Se II laser
Get PDFWe have observed cw laser action in 15 transitions of singly ionized selenium using an electron beam to excite a He-Se mixture. The variation of the laser output power as a function of the electron beam discharge parameters is reported
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