Hello again @Dan, thank you so much, it is perfect ! Very much appreciated :)

no problem (there is the same kind of typo in the denumerator, I forgot to mention). Regarding the result, I am actually not quite sure, but it looks like it is not what I had in mind. [![enter image description here][1]][1] (I did not include normalization to have zero gain at DC here) [1]: i.sstatic.net/BU0w4.png

Hi @Dan, thank you for your answer. You meant $e^{j\omega}-1$ instead of $e^{j\omega-1}$ in the expression of $\left\|G(z)\right\|^2$ I think ? Also, redoing your calcultations for $\omega_c$ and $\alpha$, I get the same results :)

Hello @DilipSarwate, thank you for your answer. You are right, if I have the term $B_k(t)$ in the expression of $f_c(t)$ I will indeed have a real component inside the exponential, thanks for pointing that out. So, if I only keep the $A_k(t)$, is the expression then that of a FSK signal ? Have a nice day, Alex.

Hello @MarcusMüller. I am coming back to you because it has been one week now and I still did not manage to write the blocks to make what I want. I have written a block cmp_avg_pow which work function computes output_items[0][:] = np.mean( input_items ) (np being short for numpy) and another block, custom_thres which work function just make output_items[0][:] = blocks.threshold_ff(0.0, input_items[-1], 0). In my main function, I connect complex_to_mag_squared blocks to both cmp_avg_pow and custom_thres, and the output of cmp_avg_pow also to custom_thres. Nice day,Alex

Okay will do, thank you

@MarcusMüller oh okay I thought it was like that I had to do. I am going to search how to access the value rather than access the whole block. Thank you for your answer :D

@MarcusMüller I tried to just print the values given by the complex_to_mag_squared block, and was expecting to see some float values. Insted, I got something like this all_cmpl_to_mag2[0] = <gr_block complex_to_mag_squared (4)>. I do not understand how to get the value from there ?

Thank you for your answer @MarcusMüller, I will try by simple connection. Have a nice day, Alex