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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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Experimental determination of pulse code modulation signal to noise ratio, and methods of signal analysis for pulse code modulation analog data
Experimental random signal radar system using sample function from stationary Gaussian random process as transmitted signal
Noisy synchronizing signals effect on noncoherent frequency shift keyed split phase coded system performance, noting signal to noise ratio degradation
Optimal signal selection for transmission over channel with clutter noise component increase as function of signal energy
Error rate from FSK binary signal detection calculated using FM discriminator for FM signal with nonselective fading in Gaussian noise
Method of processing data from a spacecraft, where the carrier has a low signal-to-noise ratio and wide unpredictable frequency shifts, consists of analogue recording of the noisy signal along with a high-frequency tone that is used as a clock to trigger a digitizer.
Time-shared integrate-hold-dump circuits separate the dc level due to the signal /bit information/ from the dc signal due to the baseline error. The system detects the baseline error, filters it, and then algebraically adds enough voltage to a servo loop to reduce the error to zero.
Output signal to noise ratio of bandpass limiter calculated for phase modulated signal
Hard limiting effect on sum of three or four sinusoidal signals noting output amplitudes, signal suppression and negative suppression effect
Latitudinal cut-off of manmade VLF signals in short path through ionosphere to OGO 2 satellite, noting strong noise following signal cut-off
Subcarrier phase modulated single sideband sinusoidal carrier synthesis, discussing signal power ratios, signal efficiency, design sensitivity, etc
Circuit, placed in the signal path of a closed-loop receiver to modulate telemetered data in the 10-MHz spectrum, improves signal-to-noise ratio by 3 db in a communication receiver. The switch enables bandwidth reduction which reduces noise overload on the following stages, giving the system greater dynamic range.
Device determines average rms value of buffet signals by integrating rms signals from strain gages for preselected period of time. System measures average rms value of other transient data, and the upper frequency limit depends on the frequency response of the amplifiers.
Lamp modulator provides visible indication of presence and magnitude of an audio signal carrying voice or data. It can be made to reflect signal variations of up to 32 decibels. Lamp life is increased by use of a bypass resistor to prevent filament failure.
Optimum signals for phase locked or delay locked loops determined as function of signal to noise ratio
Signal processor with ratio-squared predetection combining for adaptive antenna array, discussing radiation patterns for coherent and incoherent signal and noise sources
Signal design for Gaussian noise and intersymbol interference immunity, discussing bandlimited signals and maximum likelihood detection technique
Hard limiting bandpass limiter output signal to noise ratio in PM signal detection calculated using probability density function