control Linear analysis error due to sample rater?

my Objectif is to get a frequency response of the open loop system of plant which will allow me to design the controller transfer function. after including the RMS filter, the Analysis tool of Simulink shows this error:

Simulink Control Design 1 Clear 02:22 PM Elapsed: 0.29 sec In "frestimate(modelname,op,io,in)",
the input signal "in" is a frest.Sinestream signal which has parameter values for "Frequency" and "SamplesPerPeriod" such that it inherently 
has multiple sample times. Using such an input signal requires that samples rates belonging to the Simulink signals
where your linearization input and output points are located are either continuous 
or fixed in minor time step and the linearization I/O io(2) does not satisfy this requirement.
Consider either changing the sample time of Simulink signal where io(2) is located to continuous sample time 
or using frest.createFixedTsSinestream utility to create a sinestream signal that has a single sample rate.
Component:Simulink Control Design | Category:Frequency Response Estimation error
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what I understood is that I have to use only one sample frequency which I cannot since i need the RMS filter. how can I get my frequeny response?

Answer 1

[Siddharth Jawahar]

Hi TarikTech,

This most probably seems to be an issue with a sample time mismatch at the linear analysis IO points. Please make sure you have the same sample time of the Simulink signals at which you inject the sinestram signal and also record the output.

Best,

Sid