Software Defined Radio
Aus DL8RDS Wiki
DSPs can do so many funny things that they have long started to change radio technology. But figure out that modern DSPs can sample signals of far above 1 GHz! You can thus process and generate all conceivable wave forms and transmission standards right within one chip! Of course, there's a little more to it, but nevertheless. Here's a collection of interesting projects. You know, my focus is on Open Source technology, so I will prefer Open Source compatible hardware here: