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文件名称：多分量滤波器去除可控震源谐波
文件大小：335KB
文件格式：PDF
更新时间：2012-08-26 10:20:03
谐波
A harmonically distorted vibroseis signal is decomposed
using the “multiple filter technique” in a similar
manner as the wavelet transform. The 1-D vibroseis
signal is transformed into a 2-D function of time and
frequency. The procedure consists of applying a family
of narrow Gaussian filters whose center frequencies are
close to the instantaneous frequencies of the harmonically
distorted vibroseis signal. As a result of this decomposition,
an envelope trace is obtained for every center
frequency. For a linear fundamental (pilot) sweep, the
fundamental sweep and its harmonic distortions have
different arrival times in the decomposed envelope trace.
An accurate analysis of the harmonic distortion can be
carried out using the amplitudes along the slopes of
the instantaneous frequency defined for the linear fundamental
sweep and its harmonic distortions. Plotting
the contoured amplitudes of each envelope trace on a
frequency-versus-time scale yields the amplitude distribution
between the fundamental sweep and its harmonic
distortions. They represent the frequency content of the
uncorrelated vibroseis signal and can be used to examine
the interaction and leakage of the signal and its harmonics.
Similarly, the correlation noise, the so-called “ghost
sweep” in the correlated vibroseis data, can be decomposed
with this technique. The method is applied to synthetic,
harmonically distorted, vibroseis signals and to a
real vibroseis vertical seismic profile (VSP) data set.