@TomGeorge @johnerrington
The measurement results are attached.
First is the wiring considering Analog GND and Digital GND.
The blue color is the "star connection" and the orange color is the same wiring as before.
Unfortunately, I don't think there is a noticeable difference. Incidentally, there was no significant difference when a capacitor was placed between VDD and GND of ADS.
Next is the result using the differential mode (A0-A1), compared with the difference between A0 and A1 in the single-end mode. The blue color is the single-end mode and the orange color is the differential mode. The blue color is single-end mode and the orange color is the differential mode.
By the way, I read a blog that showed an example of installing an OP-Amp voltage follower.
I tried it with the LM358N that I had at hand, but it didn't reduce the noise.
Regards,