Real fft vs complex fft

1. What is the difference between a real FFT and a complex FFT?
2. What is a real FFT?
3. What is a complex FFT?
4. What are the two types of FFT?

What is the difference between a real FFT and a complex FFT?

Each of these four transforms has a complex version and a real version. The complex versions have a complex time domain signal and a complex frequency domain signal. The real versions have a real time domain signal and two real frequency domain signals.

What is a real FFT?

The real portion of an FFT result is how much each frequency component resembles a cosine wave, the imaginary component, how much each component resembles a sine wave.

What is a complex FFT?

An example of an application where you use complex FFT is when the signal consists of both a real and an imaginary component. A signal consisting of a real and an imaginary component occurs frequently in the field of telecommunications, where you modulate a waveform by a complex exponential.

What are the two types of FFT?

These are called the radix-2 and mixed-radix cases, respectively (and other variants such as the split-radix FFT have their own names as well).