Editing wave distortion

Hello, I am new to the forum and relatively inexperienced with Audacity but I am looking to remove this change in level every two seconds or so. I would like to shift it down so it would be centered at zero and the recorded sine wave would be symmetrical above and below zero. This is a scaled down recording of line voltage in a house and I believe these jumps are due to the actual hand held recording device rather than actually real dististurbances on the line voltage. If anyone could recommend the best way to remove these, it would greatly be appreciated.

That’s power line voltage at 50 or 60Hz? Try a high-pass filter at around 50 or 60 Hz, depending on where you live.

A high-pass filter will also remove any DC offset/bias, since DC is zero Hz.

Note that the filter cut-off is defined as 3dB down, no matter how sharp the filter. So for example, if you don’t want 60Hz attenuated by 3dB, maybe set the filter for 50 or 55 Hz, etc.

It is 60HZ. I played around with the high pass filters a little and it did help but it also somewhat distorted the measured disturbance I really want to see. I will try using 50 or 55hz for the high pass. Thanks.

Here is the zoomed in section of the actual measured disturbance I want.

Then here it is with a 50hz high pass on it. It unfortunately distorts this too much.

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