Guten abend,
Georg Holzmann wrote:
There is probably some nifty trignometric relation that quickly solves: Rsin(2 pi f t + arctan(B/A))=Asin(2 pi f t)+Bcos(2 pi f t)
the relation is easy: from fft or rfft you get for each bin a complex number, let's say (a + b*i) - so a is the left outlet, b the right one ... if you want polar notation: magnitude = r = sqrt(a^2+b^2) phase = phi = arctan2(a/b)
and: (a+b*i) = r*e^(i*phi) = r*(cos(phi) + i*sin(phi)) and you have r and phi now ...
Wait, (a+b*i) = frequency? If so that makes more sense as to why even use imaginary numbers. I don't really understand imaginary numbers - there more difficult for me then when I learned about inclusion in jr. high. So if I want to solve for frequency I need to know what sqrt(-1) = i is?
convert to polar, multiply the frequencies, divide by niquist (I have no
you don't have to divide by nyquist, you have to divide by the blocksize, only to normalize it ... and you will also need a window (hanning or so) for your signal, if you want to avoid artifacts ...
It seems like if I multiply the two signals frequencies togeather all the frequencies would shift way up, so I have to scale them back down somehow, right? Isin't convolution freq(sig1)*freq(sig2) and freq-mag(sig1)*freq-mag(sig2)? Maybe I just don't understand what convolution is trying to achieve.
Thanks again for all the help! -thewade