Hello,
I'm not entirely sure what exactly you're looking for. If you are looking for a way to draw random numbers from a zero mean Normal distribution, you can use the random number block: https://www.mathworks.com/help/simulink/slref/randomnumber.html
If this is not what the block that you need, then it might be easier for the community to provide some better assistance if you provide some more details about your work flow and what the block you're looking for should be doing. There was a post on MATLAB answers that you may find helpful for getting a better and quicker return on questions you post here: https://www.mathworks.com/matlabcentral/answers/6200-tutorial-how-to-ask-a-question-on-answers-and-get-a-fast-answer
