From Friday, April 19th (11:00 PM CDT) through Saturday, April 20th (2:00 PM CDT), 2024, ni.com will undergo system upgrades that may result in temporary service interruption.
We appreciate your patience as we improve our online experience.
The THD is around -110dB. I thought that the spectrum analyzer is loading it adervsaly so I decided to terminate the input of the spectrum analyzer with a 1Meg ohm with 200pF cap in parallel. After I did this the results improved dramatically. not the second harmonic is down around -100dB. See Attachment. I believe I can get better results by terminating the input of the ADC with 1Meg ohm with 200pF cap in parallel.
