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Converter can be used for automatic spectrum analysis. Automatic gain amplifier digitizes RF amplitude, and amplifier gain is measured by binary counter. Amount of gain corresponds to signal level and is proportional to count in counter. System can be used to calculate AM and FM modulation index and other parameters of pulse-modulated FM waves.
A power-spectrum and cross-spectrum analysis has been made of measurements of temporal fluctuations of intensity observed in the K-line wing (2.07 A from line center) and of simultaneous measurements of temporal fluctuations of Doppler displacement of the cores of 3931.122 Fe I and 3933 Ca II (K3). The measurements were made in a quiet region near the center of the sun's disk. We find that the average power spectra of the intensity fluctuations have two significant peaks of about equal strength: one at 0.0033 Hz (300-sec period); and one at about 0.001 Hz (1000-sec period). The average rms value of these intensity fluctuations is 0.0435 plus or minus 0.0082. Maximum brightness comes before maximum violet displacement of the Fe I line.
Complex digital computer is not required, only summing amplifiers and attenuators are used for transformation of signal. Continuous transform system may be used for spectrum analysis, filtering, transfer function synthesis, and communications.
The lunar surface gravimeter which was emplaced on the moon by the Apollo 17 flight is described and a schematic diagram of the sensor is provided. The objective of the lunar surface gravimeter is to use the moon as an instrumented antenna to detect gravitational waves. Another objective is to measure tidal deformation of the moon. Samples of signals received during lunar sunrise activity and during quiet periods are presented in graph form based on power spectrum analysis
Experimental results and conclusions are presented about the noise characteristics of gears as a function of their operating conditions. The interpretive possibilities offered by real time noise and vibration spectrum analysis are emphasized. The noise reducing effects of light weight insulation boxes are also discussed.
Both experimental and theoretical studies are presented on spectrum analysis of nuclear quadrupole resonance of antimony and arsenic tellurides. Numerical solutions for secular equations of the quadrupole interaction energy are also discussed.
The distribution of redshifts of 222 radio galaxies has been subjected to a power-spectrum analysis. No statistically significant spectral peaks are present for galaxies showing normal absorption-line characteristics; on the other hand, significant spectral peaks are present for those exhibiting strong emission features. Of these spectral peaks, the most significant, at a wavelength of 0.031 in redshift, occurs for those strong-emission radio galaxies which are also compact. The result is consistent with the proposal suggested earlier by Burbidge that the nonrandom features, which may suggest intrinsic redshifts, are confined to those objects - QSOs, N systems, etc. - in which radiation from stars does not dominate. Possible explanations of the apparently nonrandom features are briefly discussed. Finally, a table of the most recently published small-redshift QSOs and compact emission-line galaxies is presented. The redshifts appear to conform to the 0.061 (or 0.031) periodicity found earlier.
By means of spectrum analysis of select components of the tropospheric and lower stratospheric energy cycle in the Northern Hemisphere (20 N to the pole), we are able to demonstrate the existence of a 14-16 day cycle in the atmosphere. The principal energy transfer of this cycle is the conversion from zonal available to eddy available potential energy in the troposphere. This is accompanied by an energy exchange from eddy available potential to eddy kinetic energy and thence by means of the pressure-work effect at the stratospheric boundary to the eddy kinetic energy in the stratosphere. The possible physical forcing functions of this cycle are discussed.
Hard X-ray bursts have been observed from two 1B flares located in the same sunspot region and separated in time by about 70 minutes on Dec. 8, 1970. The bursts are composed by many 'flashes' of 2 to 20 seconds duration. Power spectrum analysis reveals no strong periodicities although a significant peak appears at 7.5 sec. The characteristic times of 2 to 20 sec do not seem likely to be electron transit times since the flare size is so small. These times are evidently connected with the acceleration of the electrons. Fitting Takakura's model of the radio noise region to the observations, this region is found to be small, but the density of electrons above 100 keV is high, on the order of 10 million per cu cm.
An input analog signal to be frequency analyzed is separated into N number of simultaneous analog signal components each identical to the original but delayed relative to the original by a successively larger time delay. The separated and delayed analog components are combined together in a suitable number of adders and attenuators in accordance with at least one component product of the continuous Fourier transform and analog signal matrices to separate the analog input signal into at least one of its continuous analog frequency components of bandwidth 1/N times the bandwidth of the original input signal. The original analog input signal can be reconstituted by combining the separate analog frequency components in accordance with the component products of the continuous Fourier transform and analog frequency component matrices. The continuous Fourier transformation is useful for spectrum analysis, filtering, transfer function synthesis, and communications.
Electronic transition moments of seven C2 singlet and triplet band systems, which are in the 0.2 to 1.2 micron spectral region, have been measured. The measurements were made in emission behind incident shock waves in C2H2-argon mixtures. Narrow band-pass radiometers were used to obtain absolute measurements of shock-excited C2 radiation from which absolute electronic transition moments are derived by a synthetic spectrum analysis. New results are reported for the Ballik-Ramsay, Phillips, Swan, Deslandres-d'Azambuja, Fox-Herzberg, Mulliken, and Freymark systems.
Spectra of Nova Herculis 1934 taken during an episode of intense CN absorption are analyzed to determine the isotopic abundance ratios of C12/C13 and N14/N15. Synthetic spectrum analysis, based on the wavelengths, excitation potentials, and oscillator strengths for the CN lines, and radial velocity measurements indicate that C(12)N(14) was the dominant species in the Nova, and that the minimum abundance limit for C12/C13 is about 1.5, while the minimum for N14/N15 is about 2. The results are compared with predictions based on models of thermonuclear runaways in hydrogen-rich envelopes of white dwarfs. It is noted that the nova material may have been contaminated with C13-rich material prior to or during the eruption. Possible causes of this isotope enrichment are presented.
Results are reported for direct measurement of intensity fluctuations and photographic subtractions of simultaneous Doppler filtergrams of H-alpha oscillations in sunspot umbrae. The observational techniques are described, and data are presented on the intensity variations, power spectra, and specific characteristics of the oscillations. Periods for the velocity oscillations are obtained by power spectrum analysis. It is found that the oscillations are apparently continuous, and that each umbra has its own characteristic period ranging from 145 to 180 plus or minus 10 sec and a duration of at least 8 cycles. A Doppler shift of 10 km/sec, an oscillating element size of 3 sec or less, and visibility to a radius vector of about 0.9 are also observed.
Periodic time variations in the emission of quiet solar regions were sought with the NRAO three-element interferometer at 3.7 and 11.1 cm. The visibility function of a source as obtained with a tracking interferometer is an implicit function of time, because of projected baseline changes, and therefore only observations taken when the baseline changes vary slowly with time were used. The visibility function shows significant time variations, but a power-spectrum analysis of the data revealed no unique periodicity.
By means of spectrum analysis of 11 years of lower stratospheric daily winds and temperatures at Balboa, Ascension and Canton-Singapore, evidence is presented supporting the existence of two principal wave modes with periods of about 11-17 days (Kelvin waves) and about 4-5 days (mixed Rossby-gravity waves). The structure of the two wave modes, as well as the vertical eddy momentum flux by the waves, is shown to be related to the quasi-biennial cycle, although for the mixed Rossby-gravity waves this is obvious only at Ascension. In addition, the Coriolis term, suggested as a source of vertical easterly momentum flux for the mixed Rossby-gravity waves, is investigated and found to be of the same magnitude as the vertical eddy flux term. Finally, we have examined the mean meridional motion and the meridional eddy momentum flux for its possible association with the quasi- biennial variation.
Absolute transition-probability parameters are reported for seven band systems of the C2 molecule. These include all the known C2 band systems in the spectral region between 0.2 and 1.2 microns with the exception of the Messerle-Krauss system. To obtain the data, absolute intensities of selected spectral regions were measured behind the incident shock wave in a combustion-driven shock tube containing 85% Ar and 15% C2H2. These measurements were converted into electronic transition moments by a synthetic spectrum analysis. The electronic transition moments were then used to determine extensive tables of the transition-probability parameters for each of the band systems measured.
Near field acoustic measurements were obtained for a model supersonic air jet perturbed by a screen. Noise reduction potential in the vicinity of the space shuttle vehicle during ground launch when the rocket exhaust flow is perturbed by a grid was determined. Both 10 and 12 mesh screens were utilized for this experiment, and each exhibited a noise reduction only at very low frequencies in the near field forward arc. A power spectrum analysis revealed that a modest reduction of from 3 to 5 decibels exists below a Strouhal number S sub t = 0.11. Above S sub t = 0.11 screen harmonics increased the observed sound pressure level. The favorable noise reductions obtained with screens for S sub t 0.11 may be of substantial interest for the space shuttle at ground launch.
The electronic transition moment of the A 2 Pi-X 2 Pi band system of ClO has been determined from spectral emission measurements behind incident shock waves in Cl2-O2 mixtures. The temperature of the radiating gas was typically 3500 K. Narrow bandpass radiometers were used to obtain absolute measurements of the ClO emission from which electronic transition moments were derived by a synthetic spectrum analysis. Absolute measurements of the O2 Schumann-Runge system and the photo-dissociation cross section of ClO are also reported.