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951.
A measure of analog correlator performance is considered and interpreted reted as an output signl-to-noise ratio. This quantity is shown to depend on the fourth-order expectation of the input signals and the characteristics of the integrating system. Based on the output signal-to-noise ratio, figures of merit are established for correlators utilizing an ideal low-pass filter, an RC filter, and a finite time integrator. These figures of merit indicate to what degree the correlators reject noise components. For jointly Gaussian inputs, the variation of the output signal-to-noise ratio with the input signal-to-noise ratio is shown to be independent of the integrating system. Finally, a graphical comparison indicates the characteristics of the three systems for several different parameters. This comparison shows that the finite time integrator is superior to the other two systems considered. 相似文献
952.
Space radiation dosimetry with active detections for the scientific program of the second Bulgarian cosmonaut on board the Mir space station. 总被引:1,自引:0,他引:1
J V Dachev TsPMatviichuk YuN Semkova R T Koleva B Boichev P Baynov N A Kanchev P Lakov P T Ivanov YaJTomo V M Petrov V I Redko V I Kojarinov R Tykva 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1989,9(10):247-251
A dosimetry-radiometry system has been developed at the Space Research Institute of the Bulgarian Academy of Science to measure the fluxes and dose rates on the flight of the second Bulgarian cosmonaut. The dosimetry system is designed for monitoring the different space radiations, such as solar cosmic rays, galactic cosmic rays and trapped particles in the earth radiation belts. The system consists of a battery operated small size detector unit and a "read-write" and telemetry microcomputer unit. The sensitivity of the instrument (3.67 x 10(-8) rad/pulse) permits high resolution measurements of the flux and dose rate along the track of the Mir space station. We report our initial results for the period of the flight between the 7th and 17th June 1988. 相似文献
953.
954.
Chi-Hau Chen D'auteuil R.J. O'keeffe R. 《IEEE transactions on aerospace and electronic systems》1970,(2):254-257
In this correspondence, the threshold carrier power of FM/FM systems and the receiver IF bandwidth are optimized through a computer program. For a typical set of IRIG (inter-range instrumentation group) channels, it is demonstrated that the required carrier signal-to-noise ratio can be as low as 5 dB (much less than the conventional 12 dB value) in order to maintain the subcarrier signal-to-noise ratio at 12 dB, the threshold level. comparison of the optimized and the conventional taper analysis is tabulated. 相似文献
955.
Cylindrical heterogeneous detonation waves 总被引:1,自引:0,他引:1
Further experimental studies of blast wave initiated cylindrical heterogeneous (liquid fuel drops, gas oxidizer) detonation waves are described. A pie-shaped shock tube, used for these studies, was altered in certain ways so as to improve the modeling of cylindrical waves. These modifications, along with some operational aspects, are briefly discussed. The breech of the facility, where the blast wave is generated by an explosive, became distorted with usage. Results are presented which show that lower detonation velocities are realized with the damaged breech (other conditions being the same). A photographic and pressure switch wave time of arrival study was made to ascertain the wave shape. Photographs are shown which show that the waves, blast as well as detonation, are close to cylindrical. However, in some cases there is appreciable distortion of the wave front by debris ahead of the wave. Presumably this debris comes from the blasting cap used to ignite the condensed explosive. A series of experiments was conducted using kerosene drops of 388 μm diameter dispersed in air through use of a large number of hypodermic needles. Radial fuel void regions were established by cutting off the fuel flow to a number of needles. Preliminary results relating to the effect of the size of the cloud gap on detonation velocity, quenching, and the initiator energy levels required for detonation are discussed. 相似文献
956.
This correspondence describes a unique digital Doppler ambiguity resolution technique for a pulsed S-band radar. Whereas conventional methods of resolving ambiguities employ various curve fitting schemes in which the best differentiated range curve fit is compared with the Doppler derived velocity, the method described here uses the opposite approach, i.e., the Doppler derived velocity is integrated and compared with the range change over the integrating interval. The integrating approach offers the following advantages over conventional curve fitting. 1) There are no lag errors due to velocity changes, other than tracker lag induced by jerk. 2) No large storage of past data points and their weighting Constants must be implemented. 相似文献
957.
958.
A review of some of the underlying reasons for crime is presented, together with a perspective-setting view of the present status of crime in the United States. A statistical analysis of the number of repeaters is presented as the basis for a crime control system consisting of a transponder carried by each convicted person after he is released from confinement. Real-time tracking of these transponders is done by a computer-radio system; when a crime is committed a quick check shows at least who was not involved. Countermeasures and some social implications are also covered. 相似文献
959.
W.M. Alexander J.D. Corbin 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1981,1(8):107-110
Recent studies of the lunar ejecta from lunar impacts of interplanetary dust particles indicate that during favorable lunar phases, over 80% of the submicron ejecta enters the earth's magnetosphere. This “pulse” of lunar ejecta produced by the sporadic meteor background will follow the random variations of the sporadic flux. An additional enhancement of this flux can be related to major meteor showers. Since the annual periods of these showers occur during varying lunar phase angles, magnetosphere ejecta flux associated with major showers will vary depending on the coincidence of shower periods and favorable lunar phase angles. The results of an analysis of the “pulse” of ejecta flux in the magnetosphere during the Quadrantids, Geminids, Leonids, and Perseids meteor showers are presented. These results are compared to the satellite measurements of 1959 Eta and HEOS II. 相似文献
960.
A.G. McNamara D.R. McDiarmid G.J. Sofko J.A. Koehler P.A. Forsyth D.R. Moorcroft 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1982,2(7):145-148
One instrument of the Canadian Auroral Network for the Open Program Unified Study (CANOPUS) is a pulsed dual bistatic auroral radar system (BARS) for the mapping of ionospheric electric fields, using the STARE technique originated by R.A. Greenwald [14]. The Canadian system is presently in the specification and design phases, with the objective of being operational by mid-1984. This paper describes the geometry of the BARS system, the design considerations, and the planned data and control network. 相似文献