Pseudorandom sweeping and system testing for seismic vibrator
Fan Dan-dan · Optics and Precision Engineering · 2009
To improve the resolution and Signal to Noise Ratio(SNR) of seismic signals,the sweeping mode of pseudo-random code of a seismic vibrator was investigated.The sweeping mode of binary pseudo-random code was discussed,then a new sweeping mode for ternary pseudo-random code was presented.The principle of the pseudo-random code was researched and how to generate the pseudo-random code was given.Based on the obtained pseudo-random code,a pseudo-random code sequence was designed for practical applications.Furthermore,a signal generator of ternary sweeping for the pseudo-random code was embedded into the vibrator,and tested results show that modulation frequency has significant effects on the final self-correlation results.Analysis results on self-correlation function indicate that the SNR obtained from the sweeping mode of ternary pseudo-random code has been improved by 9% as compared with that of the sweeping mode of binary pseudo-random code,which means that obtained sweeping signals are suitable for the seismic exploration.