Hi,
There are code generator modules in the many standard FPGA libraries. You may use it or you may design your one code generator. By sampling at different frequencies you will get signal at different dopplers.
You have to be more explicit on what you want.
B R
Madhukar
I don't konw what you want to generate. if you want to generate PN code, it is very easy. and you can have a lot of chance; you can program code to complete it. or you can make use of schematic, and so on.