In order to study the atmospheric pressure perturbations produced by the passages of gravity and acouatic-gravity waves through the atmosphere, a sensitive rate of change instrument (microbarovariograph) is developed. Consequently, the technique is recommended for analysis of signals from LOFT eddy current based pressure transducers. Using phase sensitive signal detection, the absolute pressure more » measurement error is reduced by a factor of at least three as compared with the error in measured pressure as related to the uncompensated signal output. Significant reductions of measurement error result from use of the signal compensation technique. Signal modification methods employing two excitation frequencies and detection by phase-sensitive techniques proved very effective. A cylindrical copper enclosure around the transducer envelope reduced transducer signal response to imposed temperature variations. Methods of reducing the error during transients have centered on providing thermal shields around the 500 kHz eddy current type transducer and on modifying the signal conditioning. The fuel rod plenum gas pressure sensor for Loss-of-Fluid-Test (LOFT) reactor exhibits measurement error when immersed in a dynamic temperature environment. Consequently, that technique is recommended for analysis of signals from LOFT eddy current based pressure transducers. However, as compared with pressure as determined from the uncompensated signal, the technique using phase sensitive signal detection reduces absolute pressure measurement error by a factor of three and is more generally applicable. Significant reductions of measurement error result from use of either of these signal compensation techniques. Signal modification methods employing two excitation frequencies and detection by either amplitude or phase-sensitive techniques proved effective. A cylindrical copper enclosure around the transducer envelope proved more effective than an evacuated thin stainless steel tube for reducing transducer signal response to imposed temperature variations.
The fuel rod plenum gas pressure sensor for Loss-of-Fluid-Test (LOFT) exhibits measurement error during temperature variations as shown during development and qualification tests.