The FFT is such a beautiful thing. I mean, what could one expect from such a complex and useful function? Especially in C?!
I’m currently assisting with my senior project team in working with some C code. And we have just seen the greatest thing ever.
Twiddles.
Yes, we have Twiddles. Where would we be without twiddles? I don’t know. I bet we could never perform an FFT ever again if it were not for twiddles. Therefore, twiddles must be very important.
The FFT itself allows for complex handling of data. For our case, we’re using it to correlate our GPS code. So, without twiddles, you couldn’t use a GPS. Yes, twiddles help you find where you’re at and where you’re going.
What is a Twiddle?
Here are a few definitions I pulled from dictionary.com.
- Tilde (ASCII 1111110, `~’). Also called `squiggle’, `sqiggle’ (sic — pronounced /skig’l/), and `twaddle’, but twiddle is the most common term.
- To change something
in a small way. Bits, for example, are often twiddled.
Interesting. I think the following one closer matches what I was using:
- A small and insignificant
change to a program. Usually fixes one bug and generates several
new ones
The Twiddle with the FFT ends up being a complex conjugate that is brought in to help generate the FFT. Without the twiddle, a good FFT wouldn’t exist.
At least, thats what the code documentation is telling me. In truth, I really just want a plain FFT, with no mustard or mayo.
Thats the joy of the Twiddle. ~
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