ACOUSTIC LEAK DETECTOR Russian patent published in 2010 - IPC G01M3/24 

FIELD: physics.

SUBSTANCE: acoustic leak detector comprises series-connected piezoelectric transducers, preamplifier and a double balance mixer whose second input is connected to a heterodyne with frequency control circuits, one of which is connected to a switch, a band-pass filter and a low-pass filter, whose outputs are connected to inputs of a block of matching amplifiers, and the output of the latter is connected to a visual and audio display unit. The acoustic leak detector is also fitted with a second double balance mixer, a heterodyne, an average rectified value converter, intermediate frequency amplifier and filter, first and second comparator circuits, first and second reference voltage sources, amplitude and frequency detectors. The output of the first mixer is connected to the input of the intermediate frequency filter whose output is connected to the input of the intermediate frequency amplifier and the first input of the second mixer, whose second input is connected to the heterodyne, and the output is connected to the input of the band-pass filter. The output of the band-pass filter is connected to the input of the average rectified value converter. Inputs of the first comparator circuit are connected to outputs of the average rectified value converter and the first reference voltage source, and the output is connected to the control input of the intermediate frequency amplifier, whose output is connected to inputs of the amplitude and frequency detectors. Inputs of the second comparator circuit are connected to outputs of the frequency detector and the second reference voltage source, the output is connected to the second heterodyne frequency control circuit, and the output of the average rectified value converter is connected to the input of the block of matching amplifiers.

EFFECT: more reliable and efficient control.

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