DEVICE FOR DETERMINING CONCENTRATION OF FREE GAS IN LIQUID Russian patent published in 1994 - IPC

FIELD: control and measuring instruments. SUBSTANCE: device comprises HF generator, series-connected power amplifier and radiator, series-connected receiver, first selective amplifier and phase meter, second selective amplifier connected with receiver, and lower-frequency filter. It also has series-connected low-frequency generator, amplitude modulator and adder loaded on power amplifier input, line amplitude detector connected to output of the second selective amplifier and loaded across the lower-frequency filter on the second modulator input connected to HF generator. EFFECT: higher accuracy and noise immunity. 2 dwg