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time aligning time signals with different sampling rates

I am trying to time align two signals. My problem is however, that they have been sampled at different rates, one has been sampled at 50 Hz the other at 100 Hz will my initial approach of cross correlation work or do I now need to either model these signals or interpolate the one sampled at 50 Hz. I feel this may be a hefty task as this is real-life data and my model will have a certain amount of error.

Solution

  • You can just re-sample the 50 Hz data to 100 Hz. There are plenty of libraries and sample code out there for doing this. The basic algorithm for 2x up-sampling is:

    • insert a 0 sample between each actual sample
    • apply a low pass filter (25 Hz cut-off)

    Alternatively, if you're not interested in the higher frequency components then you can down-sample the 100 Hz data to 50 Hz:

    • apply a low pass filter (25 Hz cut-off)
    • delete every other sample