Method for detecting stochastic resonance transient electromagnetic weak signals

Abstract

The invention relates to a method for detecting stochastic resonance transient electromagnetic weak signals. Transient electromagnetic detecting receiving signals are ns (t), wherein ns (t) is equal to s (t) plus n (t), and s (t) is target signals. In the method, scale variation is carried out on the signals, i.e. the frequency domain of time-domain signals ns (t) is NS (jw), and the frequency domain of ns (mt) is shown in the specification, wherein m is a nonzero constant. The time-domain signals are compressed by m times, and the frequency spectrum thereof in the frequency domain is expanded by m times. Thus, the frequency of large frequency weak target signals in the noise received by transient electromagnetic detection is reduced to be less than 0.1Hz, the weak target signals are input to a stochastic resonance system to generate resonance, then the target signals after time-domain compression are extracted, and then the frequency spectrum of the obtained target signals is reduced. The method of the invention comprises the following steps: firstly, inputting noise to the stochastic resonance system to obtain a noise average power spectrum strength Pn; then inputting the signals to the resonance system, wherein a frequency fi which meets the power spectrum strength in the power spectrum of output signals is the resonance frequency; and reducing each resonance frequency fi to obtain the actual frequency of the target signals. The method eliminates frequency restriction of the stochastic resonance system on transient electromagnetic signals to be detected, and accurately detects the weak target signals.

Description

(1) Technical field [0001] The invention relates to a transient electromagnetic detection technology, in particular to a scale transformation-based random resonance transient electromagnetic weak signal detection method. (2) Background technology [0002] The transient electromagnetic detection method has the advantages of fast detection ability and better spatial resolution, and has been widely used in mineral exploration and hydraulic environment exploration in recent years. [0003] As we all know, the principle of transient electromagnetic detection is: the transient electromagnetic wave is attenuated by different media in each formation during the process of propagating underground, and different media have different attenuation values ​​for transient electromagnetic waves of different frequencies. Therefore, as long as the characteristic spectrum of the transient electromagnetic signal corresponding to different substances in the echo signal is extracted, the different...

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Problems solved by technology

However, the signal amplitude of the weak signal itself under the strong noise background is too small, and it is difficult to generate stochastic resonance; in addition, because the transition rate of Brownian particles between the double wells cannot keep up with the external driving force of large frequency, it is also the reason why stochastic resonance cannot be generated.

[0007] The target signal obtained by transient electromagnetic detection is a weak signal in a strong noise background, and it is not just a low-frequency signal. The existing stochastic resonance method that can effectively identify weak signals is powerless for the weak signal detection of transient electromagnetic detection

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