A Question About Delta-Sigma Modulators

[naalald]

Hi,
When designing DSMs in simulink, if you don't put limitations for the integrators outputs, they may vary much more than ±Vref. But when you put limitations for the integrators outputs, you should correct the filter coefficients to avoid saturation. How can we do this to obtain the optimum coefficients?
Thanks.

 

[jiangxb]

hi naalald,

my suggestion is that not limit the output of integrator, input the fullscale sine wave for a period of time and record the distribution of integrator's output. set the integrator gain to scale the output within the swing of integrator based on the ratio of the maximum integrator's output to reference voltage. repeat the process and round the integrator gain to a realizable value.