Performance evaluation of MT instrument by spectral analysis
Random noise and coherent interference are major factors determine the performance of MT instrument. Based on auto and cross power spectrum of channels inside MT instrument, procedure is developed to estimate noise and coherent interference inside MT instrument. At first, short circuited input is applied to all channels of MT instrument, for arbitrary two channels, coherence, signal to noise ratio (SNR),and noise spectrum, auto power, cross power are calculated for above channels. If coherence between two channels is great than 0.8, significant coherence interference exist inside instrument. noise and coherence interference can be evaluated by check auto power and estimated noise power between two channels. Secondly, all channels of instrument are connected to same random noise input, above parameters are calculated again, estimated noise power and SNR offer better estimation of instrumentsnoise. MTU-5P of system 2000 by phoenix geophysics Inc. is used for performance evaluation experiment. Experiment result shows that coherent interference, which is about 8 times random noise,exist in TS5 data; there is no significant coherent interference found in data of TS3 and TS4 times series; normalized power spectrum density of whites noise is below -150dB; it shows excellent performance in wide frequency band, but coherence interference in some frequencies need to be minimized.
Magnetotellurics noise coherence interference spectral analysis instrument
CHEN Rujun HE Zhanxiang HE Lanfang LIU Xuejun QIU Kailin
Non-seismic Survey, BGP, China National Petroleum Corporation CNPC, Hebei, China;Postdoctral Station Non-seismic Survey, BGP, China National Petroleum Corporation CNPC, Hebei, China
国际会议
The 19th International Workshop on Electromagnetic Induction in the Earth(第十九届国际地球电磁感应学术研讨会)
北京
英文
829-834
2008-10-23（万方平台首次上网日期，不代表论文的发表时间）