Error 20020 - When trying to filter raw PPG signal

[seancassidy]

I've got some Raw PPG data points, I want to split these into its AC and DC components, I was told by my supervisor to use a band pass filter with the lower and upper cutoff frequencies as 0.7 and 1.1Hz respectively, I know why I'm recieving the error as my upper frequency is higher than the sample rate, but is there a workaround?

I've attached my VI and raw data, there are no headers on the data and the left column is time in ms, the right the intensity value.

Thanks in advance for any help

[nwxan90 · Accepted solution]

Hi Seancassidy

I have attached a screen grab of how you can fix your issue. 

I have included a constant of 0.001 to give you the resolution of 1ms. 

You can find more info regarding this issue at the below link:
http://digital.ni.com/public.nsf/allkb/ABBD3A7BC25E17C8862561270058A4A0?OpenDocument

[seancassidy]

Thanks a lot, that worked as a treat.

I know this is a long shot, but I've put in an FFT transform on the filtered data, what would be the best solution for displaying the output for the entire waveform that has been filtered. 

My Current solution stands at using a waveform chart and putting the whole code in a for loop set to repeat 2559 times as that is how many data points I have.

Thanks for your help so far and for any more in advance

[nwxan90]

If I understand your question correctly you can use an express VI as shown in the attached screen grab. 

Hope this helps