scholarly journals Measured statistical characteristics and narrow-band teletype message errors on a single-sideband 600-mile-long ultrahigh-frequency tropospheric radio link

1960 ◽  
Vol 64D (2) ◽  
pp. 125
Author(s):  
E.F. Florman ◽  
R.W. Plush
Keyword(s):  
Narrow Band ◽  
Statistical Characteristics ◽  
Ultrahigh Frequency ◽  
Radio Link ◽  
Single Sideband

scholarly journals A New Fast Approximate Hilbert Transform with Different Applications

1970 ◽  
Vol 2 (2) ◽  
Author(s):  
Abdulnasir Hossen
Keyword(s):  
Signal Processing ◽  
Hilbert Transform ◽  
Narrow Band ◽  
Analytic Signal ◽  
Time Signal ◽  
Subband Decomposition ◽  
Single Sideband ◽  
Full Band ◽  
The Hilbert Transform ◽  
Band Signal

A new and fast approximate Hilbert transform based on subband decomposition is presented. This new algorithm is called the subband (SB)-Hilbert transform.  The reduction in complexity is obtained for narrow-band signal applications by considering only the band of most energy.  Different properties of the SB-Hilbert transform are discussed with simulation examples.  The new algorithm is compared with the full band Hilbert transform in terms of complexity and accuracy. The aliasing errors taking place in the algorithm are found by applying the Hilbert transform to the inverse FFT (time signal) of the aliasing errors of the SB-FFT of the input signal.  Different examples are given to find the analytic signal using SB-Hilbert transform with a varying number of subbands.  Applications of the new algorithm are given in single-sideband amplitude modulation and in demodulating frequency-modulated signals in communication systems.Key Words:  Fast Algorithms, Hilbert Transform, Analytic Signal Processing.

scholarly journals Optimization of grapevine clonal micropropagation

2021 ◽  
Vol 937 (2) ◽  
pp. 022109
Author(s):  
Natalia Doroshenko ◽  
Valentina Puzirnova ◽  
Leonid Troshin
Keyword(s):  
Bacterial Infections ◽  
Narrow Band ◽  
Ultrahigh Frequency ◽  
Physical Factors ◽  
Optimal Parameters ◽  
Plant Genotype ◽  
Clonal Micropropagation ◽  
Planting Material ◽  
Open Ground ◽  
Micro Propagation

Abstract Clonal micro-propagation ensures the production of genetically homogeneous, healthy virus-free planting material. This kind of propagation is influenced by genetic, physiological, hormonal, physical factors, and plant genotype. To increase the success of the process, it is necessary to optimize the methods of clonal micropropagation. The technology of clonal micropropagation of grapevine using a culture of apical meristems with a size of 0.1-0.2 mm was developed, the scheme of plant regeneration was improved, a new biotechnological techniques were developed for all stages of propagation. A method of processing of meristems with an ultrahigh frequency (microwave) electromagnetic field (EMF) in combination with a narrow-band laser was developed. Method for improving recovery from viral and bacterial infections using the growth regulator Emistim, Salicylic acid, the antibiotics Gentamicin and Cefotaxime was found. A method of water therapy was developed. The optimal parameters of intensity and duration of illumination were established. Ways of adaptation of healthy plants to non-sterile environmental conditions were optimised. Methods of testing of viral infection was improved. Techniques of planting healthy seedlings in film, greenhouses and open ground were developed. The creation of unique basic vine nursery in Ust-Donetsk region was the result of conducted studies.

Statistical analysis of classification

1966 ◽  
Vol 24 ◽  
pp. 188-189
Author(s):  
T. J. Deeming
Keyword(s):  
Multivariate Analysis ◽  
Statistical Analysis ◽  
Classification Scheme ◽  
Analytical Procedure ◽  
Narrow Band ◽  
Scientific Research ◽  
Maximum Amount ◽  
Amount Of Information

If we make a set of measurements, such as narrow-band or multicolour photo-electric measurements, which are designed to improve a scheme of classification, and in particular if they are designed to extend the number of dimensions of classification, i.e. the number of classification parameters, then some important problems of analytical procedure arise. First, it is important not to reproduce the errors of the classification scheme which we are trying to improve. Second, when trying to extend the number of dimensions of classification we have little or nothing with which to test the validity of the new parameters.Problems similar to these have occurred in other areas of scientific research (notably psychology and education) and the branch of Statistics called Multivariate Analysis has been developed to deal with them. The techniques of this subject are largely unknown to astronomers, but, if carefully applied, they should at the very least ensure that the astronomer gets the maximum amount of information out of his data and does not waste his time looking for information which is not there. More optimistically, these techniques are potentially capable of indicating the number of classification parameters necessary and giving specific formulas for computing them, as well as pinpointing those particular measurements which are most crucial for determining the classification parameters.

Photo-electric Hβ and uvby photometry

1966 ◽  
Vol 24 ◽  
pp. 170-180
Author(s):  
D. L. Crawford
Keyword(s):  
Narrow Band ◽  
Line Strength ◽  
Interference Filter ◽  
B Stars ◽  
Relative Line ◽  
The Mean ◽  
F Stars ◽  
Two Parameters ◽  
Filter Photometry ◽  
The Continuum

Early in the 1950's Strömgren (1, 2, 3, 4, 5) introduced medium to narrow-band interference filter photometry at the McDonald Observatory. He used six interference filters to obtain two parameters of astrophysical interest. These parameters he calledlandc, for line and continuum hydrogen absorption. The first measured empirically the absorption line strength of Hβby means of a filter of half width 35Å centered on Hβand compared to the mean of two filters situated in the continuum near Hβ. The second index measured empirically the Balmer discontinuity by means of a filter situated below the Balmer discontinuity and two above it. He showed that these two indices could accurately predict the spectral type and luminosity of both B stars and A and F stars. He later derived (6) an indexmfrom the same filters. This index was a measure of the relative line blanketing near 4100Å compared to two filters above 4500Å. These three indices confirmed earlier work by many people, including Lindblad and Becker. References to this earlier work and to the systems discussed today can be found in Strömgren's article inBasic Astronomical Data(7).

Southern Hemisphere Seti Survey: Five Years of Project Meta II

1997 ◽  
Vol 161 ◽  
pp. 611-621
Author(s):  
Guillermo A. Lemarchand ◽  
Fernando R. Colomb ◽  
E. Eduardo Hurrell ◽  
Juan Carlos Olalde
Keyword(s):  
Southern Hemisphere ◽  
Scattering Theory ◽  
Galactic Plane ◽  
Narrow Band ◽  
Neutral Hydrogen ◽  
Sky Survey ◽  
Inertial Frames ◽  
Interstellar Scattering ◽  
Extraterrestrial Origin ◽  
Spectral Channels

AbstractProject META II, a full sky survey for artificial narrow-band signals, has been conducted from one of the two 30-m radiotelescopes of the Instituto Argentino de Radioastronomía (IAR). The search was performed near the 1420 Mhz line of neutral hydrogen, using a 8.4 million channels Fourier spectrometer of 0.05 Hz resolution and 400 kHz instantaneous bandwidth. The observing frequency was corrected both for motions with respect to three astronomical inertial frames, and for the effect of Earths rotation, which provides a characteristic changing signature for narrow-band signals of extraterrestrial origin. Among the 2 × 1013spectral channels analyzed, 29 extra-statistical narrow-band events were found, exceeding the average threshold of 1.7 × 10−23Wm−2. The strongest signals that survive culling for terrestrial interference lie in or near the galactic plane. A description of the project META II observing scheme and results is made as well as the possible interpretation of the results using the Cordes-Lazio-Sagan model based in interstellar scattering theory.

Object Wave Determination by Single-Sideband Methods

1973 ◽  
Vol 31 ◽  
pp. 266-267
Author(s):  
Kenneth H. Downing ◽  
Benjamin M. Siegel
Keyword(s):  
Phase Shift ◽  
Carbon Films ◽  
Object Wave ◽  
Electron Wave ◽  
Phase Object ◽  
Heavy Atoms ◽  
Single Sideband ◽  
Thin Carbon ◽  
Additional Phase Shift ◽  
Additional Phase

Under the “weak phase object” approximation, the component of the electron wave scattered by an object is phase shifted by π/2 with respect to the unscattered component. This phase shift has been confirmed for thin carbon films by many experiments dealing with image contrast and the contrast transfer theory. There is also an additional phase shift which is a function of the atomic number of the scattering atom. This shift is negligible for light atoms such as carbon, but becomes significant for heavy atoms as used for stains for biological specimens. The light elements are imaged as phase objects, while those atoms scattering with a larger phase shift may be imaged as amplitude objects. There is a great deal of interest in determining the complete object wave, i.e., both the phase and amplitude components of the electron wave leaving the object.

Sign in / Sign up

Export Citation Format

Share Document