Hi Henrik,
If having access to the clean modulating sine wave signal is your goal I believe that an old school series circuit made of one capacitor and the primary winding of an high impedance, audio insulation transformer should do the trick.
The capacitor will eliminate the DC component and transformer will pass only the sine wave. At the secondary winding of the transformer you should have, at scale, a copy of your desired signal to process and monitor as you wish.
Some minor phase shift might be expected but everything should be affected equally.

Regards,
Nick