In order to be prudent, a simulation circuit is specially made on Multisim platform according to the original picture. The sum of 2V DC signal and 0. 1V AC signal is used as the total input signal, and zero adjustment has nothing to do with it, so the zero adjustment signal input terminal led by that potentiometer is grounded. The ratio of AC interference to DC signal in the input signal is 0. 1/2=5%. No matter how to change this resistance, there will always be clutter in the output, and the output clutter is exactly the same as the input. The ratio of AC interference to DC output is still 0. 1/2=5%!
In fact, people in the patent office are generally too lazy to conduct substantive examination. As long as the applicant pays the fee and passes the formal examination, he can generally apply for a patent. Good people should take care of themselves!
Puda2007 users proposed to add a resistor to the noninverting input terminal to ground, but it can add a resistor, which can eliminate AC interference, but the voltage amplification factor is obviously reduced to below 1!
The key point is that many problems of analog electronic technology are not clear in theory.