This question is very specific.   In a dialogue between researchers that RG inspires, it helps to ask how to solve a problem on a more general level.    The problem with this question, is that it is application specific and has limited answers.

To get started, I suggest that the Google advanced search option be used in the following way:

find pages with

all these words: matlab plot

this exact word or phrase: transfer function of a channel

This produces 8 results that includes:

https://books.google.ca/books?id=Qtd-e1NtZVkC&pg=PA175&lpg=PA175&dq=matlab+plot+%22transfer+function+of+a+channel%22&source=bl&ots=Ony0veWLah&sig=1VFMjUlHVZVdSYhYLGnlE7_zrI8&hl=en&sa=X&ved=0ahUKEwiZ_7OL-5rSAhWq54MKHWllCpYQ6AEIHDAB#v=onepage&q=matlab%20plot%20%22transfer%20function%20of%20a%20channel%22&f=false

By simplifying the Google advanced search using

find pages with

all these words: matlab

this exact word or phrase: transfer function of a channel

Roughly double the number of possible answers are found.   I hope this helps.