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GMartin · Joined: Feb 5, 2010 Posts: 308

Jarek,

For some designs I would like to view the spectrum as percent of amplitude in the fft displays. I have been trying to find a way to do this and have had no luck, Is there a way to do this or would it be possible to add the capability to the 2d and 3d fft displays?

Thanks

George

jarek · Joined: Oct 22, 2007 Posts: 1073

I think I understand, but I am not entirely sure. Percent of what? The area where the bins a displayed?

What would the 100% setting do: show one bin at full amplitude, or show all bins at full amplitude? And what would the vertical scale show?

Perhaps a simple example could clarify that.

GMartin · Joined: Feb 5, 2010 Posts: 308

Jarek,

For example, if the frequency range is 2hz to 40hz, the total amplitude would be summed. Each bin would reflect the percent of that total. f the bins were 2hz then then it would be amplitude 2-4hz/total amplitude, 4-6hz/total amplitude etc.

The layout of the display would be the same as the display is now. The vertical axis would be frequency the horizontal axis would display the percent of total amplitude contained in that bin.

I hope this is clearer.

George

jarek · Joined: Oct 22, 2007 Posts: 1073

I added a new element in the next version 3.047 - VectorCTransform. It allows to multiply a vector by a constant (or an input scalar value). I think that was the missing piece.

Here is a snippet which I think will do what you requested.

http://proatech.com/design/fft_percent.bpd

GMartin · Joined: Feb 5, 2010 Posts: 308

Jarek

Thanks as always for the quick response.

George