July 1984
·
10 Reads
·
3 Citations
An automated system which measures, coherently averages, and stores time domain electromagnetic induction responses of conductive objects and allows on‐line analysis of the data is described. The sensor portion of the system consists of a set of coils, transmit and receive circuitry situated in a remote nonmetallic laboratory. The circuitry is controlled by a specialized high‐speed data‐acquisition system which communicates, through a microcomputer, with a distant mainframe computer. Advanced inductive load switching techniques are employed and errors due to temperature variations in the coils are minimized by suitable sensor design. The user can change date‐collection parameters, such as pulse length, dwell time, and transmitter waveform shape, under program control to tailor the system to a particular application. The design also allows for easy replacement of the sensor elements; i.e., coils, receive and transmit circuitry as different applications require. This flexibility allows the system to be readily adapted for research in a number of areas that rely on measurement of electromagnetic induction responses. A typical response may be obtained in less than 1 min. The minimum time resolution of the system is 4 μs. Noise levels of 3 to 5 mV standard deviation are obtainable for 500 averages. Data are presented to demonstrate the capabilities of the system.