Commit 5a500f88 authored by thomas.forbriger's avatar thomas.forbriger
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libs/libstfinv [TASK]: add to user documentation

be more explicit with respect to the effect of tshift and irtap. tshift just
affects the output impulse response and not the filter operation.
parent 090d1cf1
......@@ -8,8 +8,12 @@ Options and parameters in common for procedures in the Fourier domain:
fdiv=d use integer multiple of d for number of coefficients
fpad=f padding factor
tshift=d delay source correction filter wavelet by d (in seconds)
in order to expose acausal components
this is applied only to the waveform of the impulse
response of the correction filter after application to
synthetic data (has no effect on convolved data)
irtap=t1,t2,t3,t4 taper impulse response of correction filter
this is applied to the correction filter before
application to synthetic data (affects convolved data)
These options define the number of samples N used for the FFT (Fast Fourier
Transform). This number N should be larger than the number of samples M in the
......@@ -35,7 +39,12 @@ This means that the impulse response is non-zero for negative time values.
Since by definition, the impulse response is output for the time interval of
the input data, these acausal components can remain unnoticed. The option
tshift can be used to shift the impulse response as obtained by inverse FFT in
order to expose acausal components.
order to expose acausal components. The time shift is only applied to the
impulse response of the correction filter before returning the impulse
response to the caller. It does not affect the convolved synthetics. If the
output impulse response is discussed with respect to the input synthetics, the
option tshift effectively shifts the temporal origin away from the origin time
specified in the input data.
A time domain taper can be applied to the impulse response of the correction
filter by using option irtap. Four time values are given in units of seconds:
......
......@@ -8,5 +8,10 @@ Options and parameters in common for procedures in the Fourier domain:
fdiv=d use integer multiple of d for number of coefficients
fpad=f padding factor
tshift=d delay source correction filter wavelet by d (in seconds)
this is applied only to the waveform of the impulse
response of the correction filter after application to
synthetic data (has no effect on convolved data)
irtap=t1,t2,t3,t4 taper impulse response of correction filter
this is applied to the correction filter before
application to synthetic data (affects convolved data)
# ----- END OF stfinvfourier_summary_usage.txt -----
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