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Message ID: 476     Entry time: Mon Feb 7 18:13:31 2011
Author: Frank 
Type: Summary 
Category: VCO 
Subject: VCO tuning - fitted function 

tried to fit  the tuning of the VCO in order to calibrate the VCO tuning voltage into frequency shift.
I've only fitted it down to -4.3V using 5 degrees as there is no change in frequency below that point anymore.
Will add an EPICS software channel which contains the calibrated data.

Linear model Poly5:
     f(x) = p1*x^5 + p2*x^4 + p3*x^3 + p4*x^2 + p5*x + p6
Coefficients:
       p1 =   0.0005513
       p2 =   -0.003731
       p3 =   -0.005932
       p4 =    -0.02587
       p5 =       1.406
       p6 =       79.99

vco-tuning_fit1.png

Using 9 degrees the fit is not as good in the valid region for the 5 degrees, but covers the entire range from -5V to 5V

Linear model Poly9:
     f(x) = p1*x^9 + p2*x^8 + p3*x^7 + p4*x^6 +
                    p5*x^5 + p6*x^4 + p7*x^3 + p8*x^2 + p9*x + p10
Coefficients:
       p1 =   4.16e-006
       p2 = -1.095e-006
       p3 =  -0.0003138
       p4 =   0.0003221
       p5 =    0.007185
       p6 =    -0.01047
       p7 =    -0.05412
       p8 =    0.006482
       p9 =       1.498
       p10 =       79.97

vco-tuning_fit2.png

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