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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.
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Modern high-performance radar systems are employing ever-more Digital Signal Processing (DSP), replacing ever-more formerly analog components. Precisely predicting the performance of digital filters and correlators requires an awareness of some of the finer points and characteristics of digital filters. We examine a representative radar receiver DSP chain that is processing a Linear Frequency Modulated (LFM) chirp.
Geophysical research on historical nuclear tests is an important aspect of future monitoring capabilities in seismic research. This research is challenging due to the limited number of digital seismic recordings during the peak of nuclear testing (1945-1992). These limited records are unique and non-reproducible data with potential high research impact. Releasing available nuclear explosion seismic records to the explosion monitoring community is thus of high value and is the motivation for this dataset release. The target of this effort was on compilation and quality control of regional seismic records of nuclear explosions recorded on Lawrence Livermore National Laboratory stations ELK, KNB, LAC, and MNV, known collectively as the Livermore National Network (LNN) (Figure 1). LNN was established in the early 1960s for the primary purpose of monitoring underground nuclear testing at the former Nevada Test Site (NTS), now known as the Nevada Nuclear Security Site (NNSS) following the signing of the Limited Test Ban Treaty (LTBT). LNN consisted initially of short-period vertical component Benioff’s recorded on film located at Mina, NV (MNV) and Kanab, Utah (KNB). LNN added two additional stations at Landers, CA (LAC) and Elko, NV (ELK) in 1967 and upgraded equipment to broadband seismometers recorded on frequency modulation (FM) tapes from 1967-1979, followed by digital recordings after 1979 (Jarpe, 1989). The digital recordings were on a variety of now obsolete media, including 9-track, Exabyte, and DAT tapes. Jarpe (1989) describes the seismic station instrumentation details over the period of deployment. LNN recorded valuable non-repeatable unique data of several hundreds of nuclear explosions at NNSS, as well as earthquakes and chemical and mining explosions (Walter, 2020). The details of these nuclear tests are provided in the Department of Energy Report NV-209 Rev 16 (DOE, 2015).
This report presents a framework for transmission line ( T-L ) sensor design in Frequency Modulated Continuous Wave (FMCW) radar applications, with particular emphasis on modeling collision damage effects. Classical electromagnetic (EM) propagation theory is combined with impact mechanics to develop a model for analyzing transmission line behavior as a sensor under high-velocity impact conditions. The framework includes detailed mathematical derivations, spatial and temporal damage evolution models, and practical implementation considerations.
Controlling the frequency of a square-loop magnetic core oscillator using a dc voltage to give a voltage-to-frequency conversion for use in pulse frequency modulated telemetry systems
Pulse frequency modulation simulator for design and testing of telemetry equipment for satellite systems
Simple circuit monitors the frequency of PFM /Pulse Frequency Modulated/ telemetry signals. This discriminator can be used as a constant current integrator in such circuits as linear sweep and time delay.
Two or more series RLC circuits are used with a negative feedback amplifier to make a voltage variable oscillator. This combination results in high phase stability and optimum frequency modulation.
Earth to Moon and lunar surface-to-surface communications using lunar satellites and FM and SSB modulation techniques
Frequency modulated system to measure surface pressures on free flight models in conventional wind tunnels
Comparison of performance of pulse frequency modulation and pulse code modulation telemetry systems
Digital data processor, circuit design and fabrication, digital word readout, and interfaces for IMP D and IMP E pulse frequency modulation encoding system
Geographical distributions of geomagnetic micropulsations continuously recorded on frequency modulated magnetic tape
Deep space frequency modulation system permits transmission of data where the signal deviation is greater than 1/2 the predetection bandwidth. It provides satisfactory performance at great distances or with low signal levels.
Development of experimental linear swept frequency modulator for aircraft satellite communications
Waveform distortion in maximum likelihood Darlington detector for M-ary pulse frequency modulation signals
Dual detection system for processing AIMP satellite pulse frequency modulated telemetry data
Saturn pulse frequency modulation telemetry data processed through predictor data compressor
Statistical analysis of pulse frequency modulation systems with white noise input