On 03/06/13 16:55, Pekka Seppänen wrote:
As it could be, that you don't know until you have your PoC running that what kind of embedded platform you do need for your implementation to be feasible. Do you need a DSP chip, 16bit or 32bit, floating or fixed point or does a multi purpose micro controller cut it.
And that's the point where you'd like stick your custom complex number class in; That tells you at what kind of level (as in how many bits) precision it operates and what kind of operations it makes. This is a bit what Matlab's Fixed Point toolbox does (I have used it a bit) but still I find a bit lacky for real life problems.
I'd say that in the end you'll write your FFT completely by hand as that's where all the processing time counts. But! You don't want to start by doing yet another FFT implementation that is off-by-one bug etc. ridden for the first few days.
As I'm not the one doing the implementation, please do regard this as a comment coming from the back row - easier said than done, that is. Just liked to share some thoughts on FFT matters that I've encountered during the years.
You can only test if precision is sufficient if you use exactly the same code in your prototype and in your optimized version though.