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.
Passive telemetry system enables the monitoring of vital biological functions from living organisms, without external connections or power sources. The FM system, using a phase locked loop technique, keeps the information frequency and powering frequencies separate.
Digital phase lock loop system is designed by smoothing the proportional control with a low pass filter. This method does not significantly affect the loop dynamics when the smoothing filter bandwidth is wide compared to loop bandwidth.
Phase-locked loop with photoresistive control, which provides both sine and cosine outputs for subcarrier demodulation, serves as a telemetry demodulator signal conditioner with a second harmonic signal for synchronization with the locally generated code.
System provides rapid command sync acquisition between widely separated transmitter-receivers. It is based on a rapid, automatic range-adjustment approach rather than the time-consuming cycle slipping or stepping techniques of conventional phase-locked loops.
Spacecraft telecommunication systems - coding methods for phase locked loops, absolute time determination by pulsar, communications elements research
Parameter space calculation for phase lock loop operation in low signal to noise environment
Synchronization in coded communication systems, considering phase lock loop and square wave correlation function
Block coded telemetry systems design for phase coherent space communication employing double conversion superheterodyne phase locked receivers
Technique uses a helical-scan video recorder with auxiliary signal-conditioning equipment to provide an inexpensive, high-capacity magnetic tape recording of a 112 channel, phase-locked, multiplexed, baseband signal.
Theory for block-coded telemetry systems is useful in testing performance of one- and two-way, phase-coherent telemetry systems when double-conversion, superheterodyne, phase-locked receiver, preceded by bandpass limiter is used to track carrier.
Tracking oscillator consists of modified phase-lock loop which controls voltage-controlled oscillator capable of automatic lock-on and track of periodic input waveform over frequency ratio 500-1. It is used in telemetry and communications systems where large signal fluctuations are encountered.
Phase-locked loop operation in multipath environment and multipath effect on detection for Mars probe
All digital phase locked loop FM demodulator, and optimum adaptive delta modulator designed for improving space communication
Performance improvement analysis for Apollo unified S band system, including computerized simulation techniques and phase lock loop studies
Threshold extension techniques using impulse noise detection and elimination implemented at phase lock loop demodulator output
Absolute frequency wideband high resolution determination, using frequency synthesizer as phase locked loop local oscillator
Delta modulation threshold extension technique for phase lock loop FM demodulator
Coherent receiver as hybrid carrier tracking loop consisting of standard phase locked and modified Costas loop