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A NOVEL FIXED‐SOURCE ELECTROMAGNETIC SYSTEM 1
Author(s) -
JOHNSON I.,
DOBORZYNSKI Z.
Publication year - 1988
Publication title -
geophysical prospecting
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.735
H-Index - 79
eISSN - 1365-2478
pISSN - 0016-8025
DOI - 10.1111/j.1365-2478.1988.tb02158.x
Subject(s) - transmitter , amplitude , waveform , electromagnetic coil , acoustics , frequency domain , optics , noise (video) , electromagnetic field , physics , dipole , time domain , computer science , telecommunications , channel (broadcasting) , voltage , quantum mechanics , artificial intelligence , image (mathematics) , computer vision
ABSTRACT A novel fixed‐source electromagnetic system has been developed. The transmitter is a large rectangular loop or grounded dipole. The transmitted waveform consists of up to five superimposed pure sinusoids at well‐separated frequencies. The receiver measures the amplitude and phase at two frequencies from a single receiver coil. The amplitude ratio is routinely calculated. Field trials with both surface and downhole configurations show that the method has advantages over the more traditional frequency‐domain Turam type and downhole electromagnetic (DHEM) systems. Among such advantages are the use of a single receiver coil and the removal of noise due to free‐space variations in transmitter‐receiver geometry. The latter is important for DHEM surveys. In terms of field procedures and quantities measured, the system is similar to time‐domain methods.