Brad: You are treating an FFT as if it were a spectrum analyzer which produces a magnitude or energy profile of how much signal is at a particular frequency. The FFT does much more than that. It tells not only what magnitude is at a frequency but what phase angle the signal has there.
Let's take an example: You would not want the fft of sin(t)+cos(2t) to be the same as sin(t)+sin(2t). You would want the result to show that the stuff at 2t is 90 degrees out of phase depending on what signal you input. Bob On Sat, Oct 11, 2014 at 5:38 PM, <k1...@comcast.net> wrote: > I can't wrap my head around why fft transform of complex signal produces a > complex output. After all the output reflects the amount of energy per > frequency bin and frequency bins and energy are both real numbers, no? > > I'm trying to write a python script to analyze the energy across frequency > bins but I don't know where to insert a complex to mag block. I think if I > can understand the fft I will know to put the complex to mag. > > Thanks > Brad. > > _______________________________________________ > Discuss-gnuradio mailing list > Discuss-gnuradio@gnu.org > https://lists.gnu.org/mailman/listinfo/discuss-gnuradio > > -- Bob McGwier Co-Owner and Technical Director, Federated Wireless, LLC Professor Virginia Tech Senior Member IEEE, Facebook: N4HYBob, ARS: N4HY Faculty Advisor Virginia Tech Amateur Radio Assn. (K4KDJ)
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