Engineering topics

Fountain, Glen H.

Publications and source records attributed to Fountain, Glen H..

2 records

NASA NTRS1992

The Hopkins Ultraviolet Telescope - Performance and calibration during the Astro-1 mission

Results are reported of spectrophotometric observations, made with the Hopkins Ultraviolet Telescope (HUT), of 77 astronomical sources throughout the far-UV (912-1850 A) at a resolution of about 3 A, and, for a small number of sources, in the extreme UV (415-912 A) beyond the Lyman limit at a resolution of about 1.5 A. The HUT instrument and its performance in orbit are described. A HUT observation of the DA white dwarf G191-B2B is presented, and the photometric calibration curve for the instrument is derived from a comparison of the observation with a model stellar atmosphere. The sensitivity reaches a maximum at 1050 A, where 1 photon/sq cm s A yields 9.5 counts/s A, and remains within a factor of 2 of this value from 912 to 1600 A. The instrumental dark count measured on orbit was less than 0.001 counts/s A.

Davidsen, Arthur F.↗

NASA NTRS1986

Patient ECG recording control for an automatic implantable defibrillator

An implantable automatic defibrillator includes sensors which are placed on or near the patient's heart to detect electrical signals indicative of the physiology of the heart. The signals are digitally converted and stored into a FIFO region of a RAM by operation of a direct memory access (DMA) controller. The DMA controller operates transparently with respect to the microprocessor which is part of the defibrillator. The implantable defibrillator includes a telemetry communications circuit for sending data outbound from the defibrillator to an external device (either a patient controller or a physician's console or other) and a receiver for sensing at least an externally generated patient ECG recording command signal. The patient recording command signal is generated by the hand held patient controller. Upon detection of the patient ECG recording command, DMA copies the contents of the FIFO into a specific region of the RAM.

Fountain, Glen H.↗