How to create a matlab plot that displays two horizontal axes (each with a different x-tick), with one axes on the bottom and one on top?

I'm taking signals class and something like this would come in handy.

https://en.wikipedia.org/wiki/Sinc_function

Answer 1

[Walter Roberson]

http://www.mathworks.com/matlabcentral/fileexchange/317-plotxx-m and similar contributions to the file exchange