Hi everyone,
First post here, so be gentle. I'm analyzing scientific data of a pulse, which has an asymmetric shape. The data I'm trying to analyze is time vs. signal. I've learned by searching this forum how to find the time associated with max signal. Now I'd like to find the time at 1/2 and 1/4 the signal. I've tried adapting the formula that I learned here to do that, but I can't get it to work correctly. Need some help.
Here's the formula to find time at peak height.
=INDEX(D1:D200,MATCH(MAX(E1:E200),E1:E200,0))
I tried to modify it to find 1/2 by doing
=INDEX(D1:D200,MATCH(0.5*MAX(E1:E200),E1:E200,0))
but I get weird values or an error. The 0 at the end makes it exact, which causes a problem, so I tried a 1 and -1, but that didn't help in all cases. Since the data is a spike, there will be 2 times associated with half the max, and I only need the one on the downswing. I tried changing the range to something like
=INDEX(D100:D200,MATCH(0.5*MAX(E1:E200),E100:E200,0))
but again, I'll get either an error or the wrong answer.
Need some help.
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