suaddnoise

seismic software,very useful

SUADDNOISE - add noise to traces
suaddnoise <stdin >stdout  sn=20  noise=gauss  seed=from_clock
Required parameters:
	if any of f1,f2,f3,f4 are specified by the user and if dt is
	not set in header, then dt is mandatory
Optional parameters:
	sn=20			signal to noise ratio
	noise=gauss		noise probability distribution
	seed=from_clock		random number seed (integer)
	f1=0.0			left  low  corner frequency (Hz)
	f2=0.0			left  high corner frequency (Hz)
	f3= nyquist		right low  corner frequency (Hz)
	f4= nyquist		right high corner frequency (Hz)
	dt= (from header)	time sampling interval (sec)
NOTES:
	Output = Signal +  scale * Noise
	scale = (1/sn) * (absmax_signal/sqrt(2))/sqrt(energy_per_sample)
	If the signal is already band-limited, f1,f2,f3,f4 can be used
	as in suband to bandlimit the noise traces to match the signal
	band prior to computing the scale defined above.