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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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At least 37 records · Page 2

P-ACTIVE (PCM-Based Actively Tunable Filter) Project at NASA

Phase change material (PCM)-based actively tunable mid-wave IR filters have broad imaging and sensing applications—from probing molecular vibrations in chemical species to detecting radiant thermal signatures. We introduce the Phase-change actively tunable filter (P-ACTIVE) project lead by NASA Langley Research Center with collaborators MIT and the University of Cambridge. It covers background science, experimental and theoretical device performance, as well as recent results obtained from a MISSE-14 mission for space qualification of active metasurface optics and constituent PCM. We conclude with a prospective view of the technology and discuss the potential for these filters to serve multiple NASA missions.

phase change material↗

PCM picture transmission.

PCM picture transmission, pseudorandom scanning, noise, bandwidth compression and digital simulation

BANDWIDTH↗

Burst retransmission of PCM telemetry data.

Periodic burst technique for real-time retransmission of data from multiple asynchronous PCM telemetry links, providing accurate determination of individual sample time

DATA TRANSMISSION↗

PCM bit detection with correction for intersymbol interference

For pulse code modulation bits, received signals are filtered by integrate and dump filter from which samples are directed to end of PCM bit. Threshold decision circuit determines level of sample voltage. Effects of interference of known past bit can be corrected by raising or lowering threshold voltage value.

Thumim, A. I.↗