Gradient measurement method of transient electromagnetic response signal and observation device thereof

Abstract

The invention discloses a gradient measurement method of a transient electromagnetic response signal and an observation device thereof. The gradient measurement method comprises the following steps: taking the center of a transmitting coil as an origin O, taking the plane of the coil as an XOY coordinate plane and coaxially arranging two receiving devices with the same specification in parallel in the X, Y or Z direction; dividing four signal output ends of the two receiving devices into two groups, performing subtraction operation through two independent integrated operational amplifiers, then outputting two lines of signals, further performing the subtraction operation on the output signals through the integrated operational amplifier, getting a subtraction analog signal between induction electric field signals of the two receiving devices, further enabling the analog signal to form a digital signal after signal conditioning and conversion through an A / D (analog / digital) conversion circuit, and dividing the digital signal by the distance delta x between the two receiving devices to form average gradient of the transient electromagnetic response signal. The invention relates to the gradient measurement method of the transient electromagnetic response signal and the observation device thereof, which can greatly improve the signal-to-noise ratio and the abnormity resolution capacity of observation signals and provide reliable data for fine interpretation of abnormities of a target.

Description

technical field [0001] The invention relates to a transient electromagnetic response signal gradient measurement method and an observation device. It is suitable for use in transient electromagnetic exploration fields such as aviation, ocean, ground, well and roadway. technical background [0002] As a geophysical prospecting method, the transient electromagnetic method is implemented. The transmitter transmits an electromagnetic field through the transmitting coil. When the primary field is turned off or at a certain time before and after it is used as a reference, a synchronization signal is sent to the receiving instrument. The rod collects the electromagnetic induction signal of the surrounding medium under primary field excitation; usually the change value of the vertical component of the magnetic field is measured, using the formula dB Z / dt means, where B is the magnetic field, the electromagnetic induction signal is called the secondary field, which decays with time...

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Problems solved by technology

[0003] The existing transient electromagnetic method usually adopts the mode of one transmission and one reception or one transmission and multiple reception, and adopts the absolute measurement method of the secondary field. Since the mutual inductance signal of the transmitting coil and the receiving coil is superimposed on the secondary field signal, the secondary field signal in the early period Difficulties in field effective signal identification and extraction

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