Hello,
Thank you for contacting National Instruments. You can easily downsample a waveform array and apply low pass filtering using a simple combination of VIs.
Interpolation is also fairly commonly used and quick to implement in LabVIEW. Please take a look at my attached examples for more information.
I hope this helps! Please let me know if there is anything else I can do. Have a great day!
Liz F
National Instruments