AdvaRes
Advanced Member level 4
madengr said:I did this years ago to linearize a YIG oscillator for FMCW radar. IIRC I plotted F vs Vtune (F is the dependent variable), fit a polynomial, and then used Analog Devices multipliers to generate the polynomial.
If you can get a hold of Analog Devices Nonlinear Circuits Handbook from 1976 it shows how to build multipliers, dividers, RMS and LOG detectors, etc.. with opamps.
I tried this technique but I left it. As you said I plotted the Fre vs Vtune charateristic and I used the Lagrange interpollation to have a 3 degree Polynom.
My question to you madengr is how to generate this Polynom. and how to compute the bandwith of the closed loop transfert function if this VCO is used to construct a PLL ?