The new ADAU1452 is quite the beast among SigmaDSP processors. With about an order of magnitude more capability than the lowly (but quite useful) ADAU1701, one wonders what applications it may find. Its SigmaStudio toolbox presently belies all this power, as only basic filters and such are included. This of course will resolve in future versions. In the meantime, though, out of curiosity I built a capacity-sized project that attempts dynamic noise reduction for legacy recordings (tape, "AAD" CD's, etc). It's similar in concept to the system described at:http://ez.analog.com/message/122872#122872 except much larger -- 45 gated frequency channels at 1/5 octave intervals, placed in five messy hierarchy boards. It manages to fill up the -1452's entire instruction memory, and you can get a cup of coffee make coffee while it Link-Compile-Downloads to the -1452 eval board.
- Does it work? Yes, after a fashion. You need to tweak its threshold control for the type and quality of the input audio.
- Is it useful? Most legacy recordings are now long gone, or else has already been processed, so that I had trouble finding suitable material in my collection to try it on. I did find an old CD of Strauss waltzes with tape hiss -- to hear the orchestra come up from dead silence was impressive! I didn't try it with FM radio (and even that is going digital, though much more slowly than expected). For analog FM it would make more sense to separate out the L-R channel and process it alone, as that's where the noise comes from anyway.
This is by far the sloppiest project I ever made, it simply got out of hand. If nothing else it demonstrates what SigmaDSP can do right now, with even more coming in the future as advanced algorithms are developed for the -1452.