LabVIEW
How to delete unnecessary frequencies
Thank you for your continued support. This time, it would be helpful if you could tell me how to delete unnecessary frequencies after FFT analysis. The attached graph shows two types of FFT (red line and white line), each representing three frequency regions. For example, how can I delete one of the three locations and display the graph at the end?
Hi kozuka,
@kozuka32 wrote:
Thank you for your continued support. This time, it would be helpful if you could tell me how to delete unnecessary frequencies after FFT analysis. The attached graph shows two types of FFT (red line and white line), each representing three frequency regions. For example, how can I delete one of the three locations and display the graph at the end?
By using even more ExpressVIs… (Just joking!)
Seriously: try to avoid ExpressVIs when you want to learn to write good & readable code! Right now all the settings are hidden in configuration dialogs, with a lot of garbled text because you don't an English environment:
"Deleting three locations" in a plot typically is just to replace the correspondig sample data by NaN using ReplaceArraySubset on the plot data. This becomes very easy once you get rid of ExpressVIs and their DDT wires!
Your data never changes, so your while loop seems unnecessary because the result will never change. Why is it there and why do you want to spin it as fast as the computer allows, burning 100% of a CPU core??
So you apparently want to remove one of the frequency components. but what graph result do you want (the waveforms missing that frequency? The FFT graph missing that peak? Both?) How does the user tell the code which component to remove?
Also be aware that just knowing the frequency and magnitude is insufficient to remove a given frequency component from a signal. You also need to know the phase, of course.
