The 'designMultistageDecimator' function in MATLAB returns a multistage decimator object, which you can use to filter your signal. The returned object 'Hm' is a multistage decimator object, and you can use it just like you used the 'Hm' object in your previous code.
Here’s how you can apply the filter to your signal:
signal_output = filter(Hm, signal_input);
This line of code applies the multistage decimator filter Hm to your input signal signal_input, and stores the result in 'signal_output'.
So, your complete code would look like this:
Astop = 80;
TW = 0.03*fs_sampling/2;
Hm = designMultistageDecimator(dec_factor, fs_sampling, TW, Astop, 'CostMethod', 'design');
signal_output = filter(Hm, signal_input);
