Well this is not the right forum for this as focus is clearly Arduino here
Would suggest you start reading some PH.D. Thesis that are a available on the web - some are pretty old but a good read because they were written before the industry took off and designed custom chips as I mentioned in my previous post.
Today it's just not economically viable to do anything else than mass market mass volume custom chips for this.
An example doc
You can see the author was looking at a DSP + FPGA board