High pass filter not attenuating signal at start of input

Question

I have implemented digital high pass filter with below specs:
Sampling frequency = 5333 Hz
Cutoff frequency = 10 Hz
Order = 3

We are facing problem like below:
As per result shown above signal gets attenuation after $1000$ data points. How can solve this kind of issue?
Any help/ suggestion would be great and appreciable! Thanks in advance.

Hilmar · Accepted Answer

Any filter with such a low cutoff (as compared to the sample rate) will lots of time domaing ringing.
The best way of adressing this is to properly initialize the state of the filter using known properties of your system & signal, but that's fairly tricky.
In your case, there may be a shit cut though: I'm guessing that you have a large bias or DC offset in your original signal. Just subtract the mean (or maybe the mean over the first samples or so, if the bias is drifting). This should subtantially reduce the ringing.

High pass filter not attenuating signal at start of input

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