how to determin the OPA's accuracy

[yezeg]

To design a mathy oparation for Vout=K3*(K1*Vin1+K2*Vin2),So i used three opa.If the final error less than 0.1%,how to calculate the three opas' accuracy,how to get the DC gain. THX!

 

[deba_fire]

Hi

Your K1,K2,K3 must have some frequency dependence.That will determine the dc gain.Then from dc gain you can calculate the error at DC.That will be LG/(LG+1).

LG=loop gian

 

[yezeg]

thx for deba_fire's reply
the input signal frequency is about 2KHz,I want to use the switch capacitor amplifer
to implement the mathy opration. My question is there are double input signal.
the 1/1+LG is suitable for SISO, Vout=K3*(K1*Vin1+K2*Vin2) is DISO,which is two inputs and one output.
K1,is used SC OPA ,how to get the K1's error range? The same is K2 ,K3.

It's like more a math problem in the signal oparation.