Tracking secondary transducer for a cryogenic liquid level gauge

The authors have developed a tracking level gauge that allows one to lock onto a particular resonance, giving remote sensing as the first advantage and high conversion accuracy as the second, in which the frequency of the FM oscillator is adjusted by a peak-holding regulation system to be equal to the sensor frequency. This paper shows the structural diagram and explains how the guage works. This structure was used in the basic module for a multirange level gauge for cryogenic media type URK-1, which is now being regularly produced at the Ryazan Teplopribor plant. The overall error in converting the resonant frequency to digital form in the URK-1 is not more than 2 x 10/sup -4/, while the frequency shift in the sensor in measuring a liquid nitrogen level is about 16%.