All I have successfully used a running fft to sense signal frequency component = changes and used this as a trigger mechanism for an event. Could one use th= e=A0 ( I guess you call it ) power spectrum of the signal just before and d= uring the event to remove the noise? I guess you would have to use the same= time window so the frequencies would compare. Could it be a simple subtrac= tion of the "before" from the "during"? This would assume that the backgrou= nd noise didn't change in the period during an event. This could be better = than trying to shape a multi pole filter to eliminate the noise. I have fou= nd that often a portion of the event signal is in the same frequency range = as the noise.=A0=20 Regards Barry
All I have succes= sfully used a running fft to sense signal frequency component changes and u= sed this as a trigger mechanism for an event. Could one use the ( I g= uess you call it ) power spectrum of the signal just before and during the = event to remove the noise? I guess you would have to use the same time wind= ow so the frequencies would compare. Could it be a simple subtraction of th= e "before" from the "during"? This would assume that the background noise d= idn't change in the period during an event. This could be better than tryin= g to shape a multi pole filter to eliminate the noise. I have found that of= ten a portion of the event signal is in the same frequency range as the noi= se. Regards Barry |