I would add one more line: Q: What is the function of the DSP stage? 1. Makes the radio sound better 2. Everything George says about it 3. Everything Doug says about it 4. No one knows but it sorta works and is fun to play with. 5. Rockwell Collins has been doing it since 1995. <http://members.shaw.ca/farson/misc/dsprcvr.html> Cheers for now, 73, Adam VA7OJ/AB4OJ