How to determine the delay of decimation and envelop filter in AGC?

[mhamini]

My AGC works on sigma delta modulator.
The decimation filter and the envelop detector has some delay.It will cause something wrong on AGC.
How to determine the delay of the filter and how to prevent that?

 

[vadkudr]

Re: AGC

>>How to determine the delay of the filter

Check phase response of the filter in Matlab, if it is almost linear, you can find time delay as
phi(rad)/(2*pi*f(rad/sec))

Or you can check time group delay In Matlab too Be careful - time group delay is defined as D(phi)/D(2*pi*f),
where D(.) is derivative