i need to take a digital audio signal between 100hz and 3.5khz and use a radix-2 FFT to get the data bits.

The bits are represented, after the FFT, by about 235 data points. each point would be about 6hz wide, and the points are 15hz center to center apart.

The data is only valid for 8ms.

Given this data, I would then perform some simple conversion to text.

Then, I also would take some new text (message), convert to a sequence of bits, and generate audio where each bit is 15hz apart, with a width of 6hz. between 100hz and 3.5khz.

Maybe the Due isn't the right platform for this.