It is found that the input energy and momentary input energy spectra with a damping factor of 5% can be estimated from the pseudo-velocity spectra with damping factors of 0.5% and 10%.
If sampling length doesn't adapt rotative velocity, the results of calculation by FFT or periodogram analysis will lead to pseudo-periods, which distorts the principal value function terms.
若采样长度与回转速度不吻合，将会出现伪周期，使主值函数项中提取周期成分后的信号失实。
3
Theoretical deduction says that in a borehole penetrating elastic formations, pseudo Rayleigh wave does not take shear-wave velocity, but its group velocity may be very close to shear-wave velocity.