I know I will regret this in advance, and wholly expect the forthcoming flaming, however, I don't see the point creating another thread when my question pertains to the SplitRadixRealP library.

Here goes..........

I am not a novice, I am not a numbskull, but I know nothing about FFT. I have watched as many youtube video explanations as I can find and just ended up getting bogged down with Maths that is beyond me. When I did my electronics qualifications back in the mid 80's we were told FFT is a method of analyzing signals and you need a sample rate double the maximum frequency you wish to sample.

I understand the sample size will yield the same number of bins, I understand each bin to represent a single frequency.

From my limited knowledge and understanding so far, I can conclude that with a sample size of 2048, a SMP_RATE of 40000 will cover me to max frequency of 20kHz and give me frequency bins of approx 10Hz, what I am not sure of is how to determine the CLK_MAIN value.

If somebody with time and patience could explain in simple terms how to determine the relationship between these settings and correct me if any of my previous assumptions are incorrect, I would very much appreciate it.

Once I have all of this clear in my own mind, I could then do with knowing how to make use of the data collected.

Many thanks,

Regards,

Graham

EDIT: So my question was stupid and premature............... I will leave it here as a record, and explain my own question for the benefit of others just starting out in the world of FFT............

`#define SMP_RATE 40960UL `

#define CLK_MAIN 84000000UL

The CLK_MAIN which I saw various values for so experimented myself........... should not be changed and is the clock speed of the DUE (84MHz), with a SMP_RATE of 40960 and sample size of 2048, the frequency step is 20Hz for example....

` 79 140 60 6 2 0 0 0 0 0 0 0 0 0 0 0 `

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

The peak value of 140 in element 1 =20Hz

` -8 2 0 0 0 0 0 0 0 0 0 0 60 142 60 0 `

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

and here, the peak value in element 13 =260Hz

I hope this helps somebody.