Butterworth high pass filter My signal's base line is around 1. When I apply Butterworth high pass filter with cut off frequency Fc = 2Hz signal's base line drops to 0. My data are from the accelerometer. Is this behavior normal ?
Yes.  A high-pass filter removes low frequencies, and a constant baseline is the lowest frequency possible ("DC" = 0 Hz), so it will be completely removed and the baseline will become 0.