Welcome to our site! EDAboard.com is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.
There are two options AFAIK:
1. Program the user-defined function to produce the desired signal (you'll have to program it yourself i'm afaraid)
2. Use the Tabulated Excitation macro. For that you'll need a file containing a 2-column signal (time and amplitude vectors).
Then you re-scale the time base and amplitude in the macro dialog box.