Electronics > Projects, Designs, and Technical Stuff
Home Brew Analog Computer System
ElectroIrradiator:
--- Quote from: GK on November 28, 2013, 11:42:31 am ---Soooo, there isn't anyone here skilled in the art of graphical Fourier analysis then??
--- End quote ---
Surely you are joking? No-one is insane enough to do a Fourier analysis by hand today, as we have these things called computers. There is no magic involved in the 'graphical method', it is just a tedious manual method of doing what your spreadsheet does better and faster. Guesstimate a coefficient for your target graph by using transparent overlays/Mk. I eyeball/experience, calculate difference and scale 'error graph', rinse/repeat for higher order coefficients.
GK:
--- Quote from: ElectroIrradiator on November 28, 2013, 12:48:53 pm ---
--- Quote from: GK on November 28, 2013, 11:42:31 am ---Soooo, there isn't anyone here skilled in the art of graphical Fourier analysis then??
--- End quote ---
Surely you are joking? No-one is insane enough to do a Fourier analysis by hand today, as we have these things called computers.
--- End quote ---
Yes, I am aware of these things called computers, I am sitting in front of one right now. I had no intention of doing the Fourier analysis by hand on paper, I was simply interested in the old methods as they may give some insight into how to more speedily estimate and manually optimize the coefficients with the aid of SPICE and/or a spreadsheet.
GK:
Well this isn't easy. Due to the complex way the Fourier components interact in the generation of a waveform, simply tweaking each coefficient one after the other and then back again for a best fit to the desired function just doesn't result in a satisfactory outcome. Attached below is my first attempt - to synthesize the X deflection waveform required to generate the figure 9. A more complex methodology for tweaking the coefficients will be required here to arrive at a satisfactory fit.
zapta:
--- Quote from: GK on November 30, 2013, 04:27:11 am ---Well this isn't easy. Due to the complex way the Fourier components interact in the generation of a waveform, simply tweaking each coefficient one after the other and then back again for a best fit to the desired function just doesn't result in a satisfactory outcome.
--- End quote ---
Can you use Excel solver or other solver to find the optimal coefficients? E.g. define some distance function and let the solver minimize it.
GK:
I really don't know. That's well beyond my familiarity with Excel right now.
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