METHOD FOR DETERMINING THE ELECTRICAL RESISTIVITY OF THE SUBSOIL BY ELECTROMAGNETIC SURFACE WAVES AND APPARATUS FOR SUBSOIL PROSPECTING BY MEASURING ELECTROMAGNETIC FIELDS

摘要

This invention relates to an improvement in the method of determining the resistance of the subsoil vertically from a given place by means of an electromagnetic surface wave emitted at a given distance from that place. The signal and the noise received at 1 are amplified and filtered at 2 and 4, while a reference signal with a constant level and the same frequency as the transmission source is transmitted to the analog multiplier 6. The maximum value of the product of the signal and the noise transmitted by 4 to the multiplier 6 and of the reference signal is taken as the proportional value of the signal received and is transmitted to the measurement device 10.