calcul_4eme_ordre - Return the zeros and the pole of a fourth order digital PLL type 2
[tau1,tau,tau2] = calcul_4eme_ordre(fn,phi,kv,icp,N,fcpf,attn)
- fn :
real. natural cut-off frequency of the open-loop transfert function [Hz]
- phi :
real. phase margin at the cut-off frequency [rad]
- kv :
real. local sensitivity of the oscillator [Hz/V]
- icp :
real. maximum charge pump output current [A]
- N :
integer. feedback divider value
- fcpf :
real. frequency update of PFD [Hz]
- attn :
real. desired attenuation at cut-off frequency of the open-loop transfert function [dB]
- tau1 :
real. zero of the transfert function of the loop filter (s)
- tau :
real. first pole of the transfert function of the loop filter (s)
- tau2 :
real. second pole of the transfert function of the loop filter (s)
- tau3 :
real. third pole of the transfert function of the loop filter (s)
//Calcul_4eme_ordre - Scilab function -
//Return the zeros and the pole of a fourth order digital PLL type 2
//Based on a NSC's Model
//13 juillet 2004 - IRCOM GROUP - Author : A.Layec
function [tau1,tau,tau2]=calcul_4eme_ordre(fn,phi,kv,icp,N,fcpf,attn)
wn=2*%pi*fn;
tau2=(-tan(phi)+1/cos(phi))/wn;
tau3=sqrt((10^(attn/10)-1)/(2*%pi*fcpf)^2);
wc=((tan(phi)*(tau2+tau3)/((tau2+tau3)^2+tau2*tau3)))*(sqrt(1+(((tau2+tau3)^2+tau2*tau3))/(tan(phi)*(tau2+tau3)^2))-1);
tau1=1/((wc^2)*(tau2+tau3));
c1=(tau2/tau1)*(kv*(icp/(2*%pi))/((wc^2)*N))*sqrt((1+wc^2*tau1^2)/((1+(wc^2)*(tau2^2))*(1+(wc^2)*(tau3^2))));
c2=c1*(tau1/tau2-1);
r2=tau1/c2;
c3=c1/10;
r3=tau3/c3;
endfunction
IRCOM Group Alan Layec