Design of helicopter transient electromagnetic transmitting and receiving circuit control based on FPGA
Based on the key problems of the transmitter's current waveform and receiving signal in transient electromagnetic:firstly,the transmitting current waveform oscillation will affect the receiving of the early signal;secondly,the amplitude of the signal after compensation is still large,but the amplitude of the secondary signal is small;finally,the production and control method of the bipolar symmetrical trapezoidal wave.In detail,the mechanism of trapezoidal wave transmission of transient electromagnetic transmit-ter and the technology of improving the dynamic range of received signal are studied.The output current waveform an ideal trapezoidal wave.The multi-frequency optional and high-power current emission can be controlled.It can make corresponding adjustments such as different geological and environmental conditions,so that the stimulation effect of the underground medium can achieve the best.In addition,multi-channel,low-noise full waveform data collection can be realized by using electromagnetic response receiving signal segmentation processing technology.The maximum launch current is developed by 320 A,the turn-off time is 800us,and the current overshoot is minimal.After compensation,the amplitude of the primary field is 0.56V,and the received signal is amplified 20 times,and the waveform is relatively regular.The transmitter has the characteristics of high integration,good stability,and strong practicali-ty,and has achieved satisfactory detection effects in many transient electromagnetic field experiments.
trapezoidal wavedynamic rangemulti-frequencyhigh power
万方数据
维普
