SEARCH · Search NASA
Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
We describe a spectroscopic measurement of the temperature and linear density of HG+ ions held in a linear ion trap (LIT). The inferred temperature and number result from analysis of sidebands on the 40.5 GHz resonance line.
We introduce a powerful Brillouin selective sideband amplification technique and demonstrate its application for achieving gain in photonix signal up- and down- conversions in microwave photonic systems.
This paper describes the MLS 177-207 GHz receiver front-end (RFE) and provides measured data for its lower and upper sidebands.
We demonstrate an efficient method for converting a phase modulated signal to an amplitude modulated signal by employing the powerful Brillouin selective sideband amplification technique.
Phase-locked oscillator system employing solid state components acts as a single-sideband modulator to accurately reproduce phase information in 2-Mc signals. This system is useful in telemetry, aircraft communications and position-finding stations, and VHF test circuitry.
Spin wave sideband in absorption spectrum at low temperatures for transition of manganese ion in antiferromagnetic manganese fluoride
Design parameters and performance characteristics for overdriven varactor upper sideband upconverter /USBUC/
Analytic function theory applications to analysis of single-sideband angle modulated systems
Double sideband suppressed carrier FM telemetry system as airborne data recorder, discussing noise, environmental conditions, laboratory and flight tests
Circuitry requires modulated subcarrier to be split, part going to a phase modulator, and part going to a new circuit which utilizes a square law detector, a balanced mixer, and an amplifier to remove spurious sidebands. A summer recombines the two outputs, and final signal no longer includes spures.
Phase locked loop with sideband rejecting properties in continuous wave tracking radar
Radiation from nonlinear polarization sideband in Ar lasers, discussing anomalous beat notes and mode locking phenomena
In this paper a definition for acquisition of a sideband modulated carrier is proposed for the phase lock loop, and the acquisition differential equation solved for a region of the modulation parameter space to determine the expected value of acquisition time. Principally the case of modulation by a single unmodulated subcarrier is considered. The numerical analysis is made for the noiseless case.
The distortion of the electron velocity distribution caused by a large amplitude Landau wave is determined analytically for the initial-value problem. The resulting stability of electrostatic perturbations impressed on the evolving plasma is studied. Narrow sidebands of the applied frequency experience consecutive growths of large magnitude during the early stages of the nonlinear wave-particle interaction. The significance of the derived results to both wave propagation experiments and triggered VLF emissions in the magnetosphere is discussed.
This paper considers digitized Weaver modulators for single-sideband modulation that can be used in radio communications and telemetering. A system of 12 such modulators to process 12 analog signals digitally is replaced by six multiplex modulators at the cost of additional computation at the input but with an overall reduction in computation time and a higher degree of accuracy. A unique digital filter is developed that can interpolate and output samples at multiples of the input sampling rate and exhibits a passband that occurs above the Nyquist frequency with no apparent distortion effects. A discussion of the Fortran simulation of a combined modulator-demodulator structure is included to verify the effectiveness of this scheme.
Description of a simple single-sideband (SSB) mixer design that yields either a sum-frequency output with the difference-frequency output suppressed or vice-versa, and uses only 'digital' logic devices and no reactive or frequency-selective 'analog' (linear) circuit elements. A pair of outputs is generated in phase quadrature. It is shown that SSB frequency conversion can be accomplished for many applications much more efficiently with simple digital circuitry than in the usual way with complicated linear frequency selective filter and phasing circuits.
Photometric and spectroscopic observations of the optical counterpart of the X-ray source H2252-035 reveal the existence of stable periodicities of 3.59 hr and 14.31 min. Both radial velocity and photometric variations occur at the longer period, suggesting that it is the true orbital period of the underlying cataclysmic binary. The shorter period appears as a 10% modulation in the light curve, superposed on the 3.59 hr variation. The frequency is the lower orbital sideband of the X-ray pulsation frequency, suggesting that the optical pulses arise from reprocessing in the atmosphere of the secondary. Unlike the majority of X-ray pulsars, H2252-035 appears to contain a white dwarf rather than a neutron star.
Sideband-aided receiver arrays (SARA's) offer way of extracting greater energy per bit in radio data signals. "Slave" receivers obtain modulation information from "master" receiver. Developed for reception of telemetry from vehicles in deep space, SARA concept applicable to commercial data-signal reception whenever two or more antennas are combined.