Cannot get downward attenuation curve from SDD21 model

[ruwan2]

Hi,
I find a SDD21 model:
https://www.ieee802.org/3/ap/public/feb06/goergen_01_0206.pdf


b1 = 2.00e-5;
b2 = 1.10e-10;
b3 = 3.20e-20;
b4 = -1.20e-30;
f = [50:15000];
SDD21 = -20*(log10(exp(1)))*((b1*sqrt(f) + b2*f + b3*f.^2 + b4*f.^3));

but I cannot get the exact attenuation curve. The above formula does not have the vertical axis (it is in range [0 -0.03]).



What is wrong?



Thanks

 

[FvM]

If you mean 15000 MHz, you shouldn't write 15000 Hz.

 

[ruwan2]

Thanks. Now I have the question of what use with SDD21. In serdes design, SDD21 gives a curve as a function of frequency. SDD21 is a magnitude. What use is it?
I think equalization should include phase, even in base band. I guess that transmitter cares about SDD21 more for energy transmission while the phase equalization is in the receiver side. Is it right?