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I am filtering a signal, and want to check if I am not over filtering it. I am doing a low pass filter, for a signal of input frequency of 512Hz, first with 250Hz pass band, then )I was intending to reduce from 250 Hz to lower frequencies. I wanted to use cross correlation , but I am not sure if it is a good technique. usually I get something like the following as Cross Correlation between the signal itself and the filtered one. i sit a good criteria?:

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  • $\begingroup$ which aspect of the applied filter, do you think, is over ? $\endgroup$ – Fat32 Dec 14 '20 at 12:52
  • $\begingroup$ thank you , I modified the question, wanted to know , for a low pass filter, how much can I go under the nyquist frequency to filter $\endgroup$ – FabioSpaghetti Dec 14 '20 at 12:56
  • $\begingroup$ You can filter as much as your signal of concern's bandwidth allows. There's no risk of overfiltering (apart from practical implementation concerns). $\endgroup$ – Fat32 Dec 14 '20 at 13:14
  • $\begingroup$ Thank you , so does CrossCorrelation mean anything here? you see that it's values change over time $\endgroup$ – FabioSpaghetti Dec 14 '20 at 13:15
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    $\begingroup$ In practice, correlation means similarity between two sets of samples. If a similarity between some sets of samples mean something for you as an indicator of overfiltering, then you can use it too. $\endgroup$ – Fat32 Dec 14 '20 at 15:52

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