synthe_frac_phase

Scicos Diagram
fr - eng

Locked fractionnal synthesizer diagram

$\epsfig{file=synthe_frac_phase_diagr.eps,width=400pt}$

Module

Modnum

Locked fractionnal synthesizer diagram

Context

//## LO
F_cpf   = 20e6
T_cpf   = 1/F_cpf
sig_ref = 0.5*%pi

//## VCO
Fo     = 2.045e9
To     = 1 / Fo
wo     = 2*%pi * Fo
kv     = 133e6
alpha  = 6.91e9
beta2  = 0.15
j_vco  = 75e3
closed = 1

//## DIVIDER
Fd     = 2.50e9;
N      = int(Fd/F_cpf)

//## DSM
DSM    = 1
DZDSM  = 1
nbit   = 16
M      = 2^nbit
K      = 3013
dither = 1
DZ     = 2*%pi*0.01/100
typ    = 3 //int32

//## PFD & CP
Icp   = 5e-3
Iup   = Icp
Idown = Icp+100e-6
Ileak = 10e-6
Ileak_sig = 0*2/100
Th    = 1e-9

//## LOOP FILTER
fn  = F_cpf/290
phi = %pi/4
kv  = kv*2*%pi
[tau1,tau,tau2] = calcul_3eme_ordre(fn,phi,kv,Icp,N)
s   = poly(0,'s')
num = 1+tau1*s
den = tau*s*(1+tau2*s)

//## Custom components
C1=820e-12
C2=150e-12
R1=1500
Rvco=5e+3
Cvco=25e-12
//tau1=C2*R1
//tau=C2+C1
//tau2=R1*C1*C2/(C2+C1)
//tauvco=Rvco*Cvco

//## LINEAR MODEL
H  = num/den                      //## loop filter
G  = kv*Icp/(2*%pi)*num/(s*den)   //##
GH = kv*Icp/(2*%pi)*num/(N*s*den) //##
kv = kv/(2*%pi)
//affiche_bode(1006,1e3,100e6,G,1+GH)

//## cont_frm
f11=cont_frm(num,den)
s11=syslin('c',f11.A,f11.B,f11.C)

//## tf2ss
f22=tf2ss(num/den,%eps)
s22=syslin('c',f22.A,f22.B,f22.C)

//## SPECTRUM ANALYSIS
winfft = 211
Tsampl = 1/100e6
nfft   = 2048*512*4
nfft   = 2048*256
onfft  = nfft/4
aver   = 64

//## SIMULATION EVENTS
Tacqui = 1e-5
Tfin   = Tacqui + (nfft+aver*onfft)*Tsampl

Scope Results

$\begin{figure}\begin{center} \epsfig{file=synthe_frac_phase_scope_1.eps,width=330.00pt} \end{center}\end{figure}$

Figure : Bode diagram of the closed loop transfert function

$\begin{figure}\begin{center} \epsfig{file=synthe_frac_phase_scope_2.eps,width=330.00pt} \end{center}\end{figure}$

Figure : Output phase noise spectra

Used blocks

Authors