Harvested crops density measuring circuit - has generator with electroacoustic transducers, filter and display

摘要

The electronic signal-generator continually produces a signal in the frequency range of 10 to 50 kHz. An electro-acoustic transducer continually reflects the signal produced by the generator into the measuring-section containing the crop. An electro-acoustic transducer receives the sound waves which have passed through the crop in the measuring-section and converts them into electric signals. An electronic filter circuit allows through only those signals with frequencies close to the frequency of the signal introduced to the filter circuit. An electronic amplitude measuring-circuit forms a voltage proportional to the amplitude of that part of the signal allowed through by the filter circuit. An indicator, regulator or calculator receives the output signal.