Audio All Pass Filter/Phase Rotator
http://vi.raptor.ebaydesc.com/ws/eBayISAPI.dll?ViewItemDescV4&item=13068...
very interesting. wonder how it would help part 15 am operations? also can you pair them into stereo and use them on part 15 fm and what good (if any) would they do there?
A little more on the circuit and what it does...