FIELD: instrumentation.
SUBSTANCE: towards the liquid surface along the normal line to it they radiate electromagnetic waves that are frequency-modulated according to linear law, reflected electromagnetic waves are received, then a signal of differential frequency is identified at the outlet of a mixer between falling and reflected electromagnetic waves, this data is saved in the form of an array of samples for the time of modulation period, the received data is approximated by a sum of two sinusoids by selection of amplitude, frequency and phase of each of them to maximum match with received data, by frequencies of received sinusoids and available distance from antennas to the bottom of the reservoir they detect dielectric permeability of liquid.
EFFECT: provision of measurement accuracy increase opportunity.
2 dwg
