Introduction - If you have any usage issues, please Google them yourself
making exponential signal with matlab
In communications, the purpose of using exponential signals instead of sinosuid ones is to use both halves of signal spectrum(Negative and Positive sides of spectrum).
For example an FSK signal can not simply downconverted to DC. because its spectrum is not symmetric around its center frequency, so you should downconvert it with exponential signal( the idea of using I and Q downconverter).