I am new to DSP, and am mostly self taught. I have a couple of questions, that may be too basic, but I couldn't really find an answer online.
I have a signal obtained by plotting the motion of a human in 2D from a fixed point of reference (origin).
- The data is noisy, so I wanted to use a filter to get a smoother signal.
- I want to filter out different motions. The intuition is that different kind of motions would occur at different frequencies.
From what I googled, and read online; it seems I need a bandpass filter like butterworth. However, after reading a few tutorials and book chapters, I have two questions:
- My signal is a time-signal (displacement vs time), but the filter takes the input in terms of cut-off frequency. Does this mean I have to convert the signal into frequency domain, or does the filter take care of it? I am bit confused on how this actually works.
- On a related note, I don't know the frequency of each motion that I am trying to filter out i.e. the intuition is that the frequency for different motions be different, but how do I determine by cut-off values? Is it usually done by trial and error, or is there a more scientific way to accomplish this?