what does 'fft~' object first ?


    Feb 12 2017 | 4:34 pm
    Hi,
    this is a very fundamental question.
    After referring back to Euler's formula, i got stuck with the object of "fft~"
    Before to know how the input signal is represented like "cos(2pi*t)+j*sin(2pi*t)" or, "cos(theta)+i*sin(theta)", what process should be done at the beginning in DSP?
    In MSP, the first two outlets of "fft~" send real and imaginary output each, then what does the object do first to derive the two results?
    In the complex coordinates (a+bi), from there 'r' and 'theta' can be derived. Then a=cos(theta), b=sin(theta) ? If so, the object "fft~" should detect "theta" from the input signal at the first?

    • Feb 12 2017 | 5:01 pm
      The [fft~] object performs a Fast Fourier Transform. It transforms data from time domain to spectral domain. Check out the MSP Analysis Tutorials "Simple Fourier Analysis" and " Advanced Fourier Analysis" to learn more about that if it's what you are after.
    • Feb 12 2017 | 7:42 pm
      >> what process should be done at the beginning in DSP?
      the first process is a DFT with only 2 bins. then the result is split into another 2 parts and then again and so on.
    • Feb 14 2017 | 3:45 pm
      While transforming data from time-domain to spectral domain in FFT, the real and imaginary parts are sent from first 2 outlets of 'fft~'. Here, in Euler's form, they are cos(2pi*f*t) and sin(2pi*f*t) each. Then, in rectangular form (a+bi), 'a' can be replaced by cos(2pi*f*t) and 'b' can be replaced by sin(2pi*f*t)?