4-PAM simulation error

I am Trying to just simulate a PAM 4 signal and demodulate it i keep getting this error.

Error in 'Pam4_modulation/M-PAM Modulator Baseband': Input must be an integer between 0 and M-1.

i am using a random interger generator block in my simulink model.

there is no output from the integer genertaor when i connect it to the 4PAM block. i would like to generate and display pam4 signal and even add noise to it. Can i understand what is the problem here.

i have attached the file to this.

[Scout Patel]

Double click on "Random Integer" . Set the size to 4

Answer 1

[Jaswanth]

Hi Siddharth,

The key to resolving the error you're encountering in your Simulink model lies in setting the size of the random integer generation correctly. For a PAM-4 (4-level Pulse Amplitude Modulation) system, the integers used to modulate the signal must range from 0 to 3, which corresponds to the four distinct amplitude levels (hence the term '4' in PAM-4).

The error message you're receiving, "Input must be an integer between 0 and M-1," indicates that the input to the M-PAM Modulator Baseband block is expected to be within a specific range. In the case of PAM-4 modulation, 'M' is 4, so the range of acceptable integers is 0 to M-1, which translates to 0 to 3.

Please refer following image for guidance.

Hope the above information is helpful in resolving your issue.