Logic for bit growth in radix-2 fft

1. What is radix 2 FFT algorithm?
2. Why do we use bit reversal in FFT?
3. What is the advantage of radix 2 FFT algorithm in comparison with the classical DFT method?
4. Why is it called radix 2?

What is radix 2 FFT algorithm?

Radix-2 algorithm is a member of the family of so called Fast Fourier transform (FFT) algorithms. It computes separately the DFTs of the even-indexed inputs (x0,x2,...,xN−2) and of the odd-indexed inputs (x1,x3,...,xN−1), and then combines those two results to produce the DFT of the whole sequence.

Why do we use bit reversal in FFT?

The FFT block enables you to output the frequency indices in linear or bit-reversed order. Because linear ordering of the frequency indices requires a bit-reversal operation, the FFT block may run more quickly when the output frequencies are in bit-reversed order.

What is the advantage of radix 2 FFT algorithm in comparison with the classical DFT method?

DFT requires no multiplies. The overall result is called a radix 2 FFT. A different radix 2 FFT is derived by performing decimation in frequency. A split radix FFT is theoretically more efficient than a pure radix 2 algorithm [73,31] because it minimizes real arithmetic operations.

Why is it called radix 2?

This algorithm is known as Radix-2 or radix of these algorithms is '2' because the N point DFT is decomposed successively such that smallest DFT size will be N = 2.