# Question about Fourier Series w/o math

1. Apr 20, 2008

Im trying to understand the process of how a microcontrollers ADC is sampling a vibration transducer and converting this into a spectrum analysis plot.

The question is about the Math part of this.

Would someone be so kind as to explain what happens to figure out what component waveforms are included in the complex input signal?

what I understand so far is the complex signal has to be periodic, then adjusted so that 50% is above/below zero?

and sines and cosines which are 90* out of phase are used because there is some constant in how they react; and there are other constants involved somehow

but how are the individual frequencies discovered? is it that you have something like a tv signal going into a mixer, the oscillator is fed into the mixer with the signal and thats how a channel is tuned in?

so taking the input complex waveform of audio, does one simply start at 1Hz and multiply "it" in there somehow and for 1Hz you get some number, and that goes into the column 1Hz? then the same for 2Hz, 3Hz... up to 20kHz?

so to find all the component frequencies and their amplitudes, one takes a period of the input complex waveform/input signal, multiplies by set frequencies and if (something) then you get the output??