The Development Of Multi-Transient Electro-magnetic Receiver

This article based on DSP-based Transient Electro–magnetic Receiver, follow the timedomain electromagnetic technology trends, designed and developed a distributedtransient electromagnetic receiver, collecting data using U disk storage, Synchronizedwith GPS clock,with ZIGBEE achieve long-distance communication.Transient electromagnetic signals in accordance with the exponential decay of thevoltage signal, it has a dynamic range more than 130dB, and very fast decay. Early,middle and late signals are all important for the geological exploration.Therefore, signalacquisition is the major difficulty.In order to expand the dynamic range of signal acquisition, we introduced theFloating-point amplification technology, by detecting the signal amplitude of amplitude,the entire cycle of the signal is divided into different intervals, using differentmagnification factor, further reduction of the follow-up processing, this very goodsampling circuit solved the problem of small dynamic range. But the introduction offloating-point amplification technology also introduces the floating-point singularity toenlarge, need to use software algorithms to filter out.Analog-digital converter chip part of a two AD, an eight other pieces 16, 8 AD chipsinto the original digital signal by the DSP after the judge size, Decided to float themagnification;16 AD chips amplified signal after the floating point is converted to digitalsignals, then sent to restore processing DSP, the results obtained shall be the actualcollected transient electromagnetic signals.In order to eliminate the system error and instrument error caused by accidentalcapture waveform distortion of the collection, this article also studies the software filteralgorithm. pass algorithm for singular point detection range position, then two endpoints of the singular point range the slope of the logarithm of the singular point ofreplacement, called primary filter. After primary filter good overall shape of waveform,no apparent Singular point.Storage of acquired signals,in order to meet the needs of the distributedmeasurement, use of U disk. DSP extended USB interface connected to U disk, Its fileoperations through the DSP program control, data read and write functions.Similarly, in order to meet the needs of the distributed measurement, this article theZIGBEE communication technology for wireless communication with the host receiver.ZIGBEE strong anti-interference, effective communication distance, through the serialport to connect with the host and the DSP, easy to use.To test the receiver performance, and the DSPdriver U disk procedures of the state,this article made a lot of hardware and software debugging and test, and analyzed theresults,.Finally, the paper also the prospect for further works.