I'm disigning a classic socond order sigma-delta modulator(CIFB structure), wiht osr=128, fs=64K,ENOB=13bits. How to determine the op gain for the first integrators?
Should the dc error at the output of the first integrators should be smaller than 1/2 LSB?
Or we can other ristrictions to determine the gain spec on the first integrators?
Another problem following, how to determine the gain requirement on the second integrator?