Is this how to measure THD+N when using a notch? Numbers seem too high (likely user error)

Hi, if you have a Notch with a gain of 0 dB followed by a low-noise amplifier with a gain of 20 dB, you have to enter this gain (20 dB) in the ‘dBV’ context menu so that the values calculated and displayed on the tiles are correct. You need to enter this gain (20 dB) in the ‘dBV’ context menu so that the values calculated and displayed on the tiles are correct. I understand from the image that places the frequency response of the Notch that it has sufficient Q so that practically the impact on the upper harmonics is negligible and thus the annoyance of exporting the Notch can be avoided. You can then use the THD dBr, THD+N dBr and SNR dBr tiles that have been set up for this purpose. Read the tread at this link to find out how to use them (this is the mode I use when I use Notch):