Scicos Diagram
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Modulated fractional frequency synthesizer

Module

• Modnum

Contents

• Modulated fractional frequency synthesizer
  • Module
  • Context
  • Scope Results
  • Used blocks
  • See Also
  • Authors

Context

lines(-1);
F_cpf = 20e6;
T_cpf = 1/F_cpf;
sig_ref=T_cpf*0.02/100

Fo = 2.045e9;
To = 1 / Fo;
wo=2*%pi * Fo;
kv = 100.5e6;
alpha=6.91e9;
beta2=0.15;
j_vco=0.2e6;

Fd=2.5e9;
N=int(Fd/F_cpf)

Nsampl = 2;
Tsampl = 1/(F_cpf*Nsampl);
Fsampl = 1 / Tsampl;

Icp = 5e-3;
Ileak=0.1e-6;
fn=F_cpf/180;
phi=%pi/4;

Ts=3/fn
Nech=12
Te=Ts/Nech
Nbit=3
M=32

[tau1,tau,tau2]=calcul_3eme_ordre(fn,phi,kv*2*%pi,Icp,N);
s=poly(0,'s');
num=1+tau1*s;
den=tau*s*(1+tau2*s);
Tfin=10e3*T_cpf 

Scope Results

Figure : (a)Charge pump output current; (b)VCO input voltage

Figure : (a)Input control symbol; (b)Filtered symbol; (c)Digitized symbol

Used blocks

• GAUSSF_c - Gaussian filter block
• GENINT_f - Random Integer Generator block (old block)
• PCLOCK_f - Integrated phase modulator event generator block
• PFD_f - Phase/Frequency tristate Detector block
• SDBLK_c - Delta-Sigma modulator block
• VCO_c - Discrete Voltage Controlled Oscillator block

See Also

• synthe_scicos - Simple scicos diagram of an integer-N frequency synthesizer (Scicos Diagram)
• synthe_eclat - Scattered diagram of a third order integer-N frequency synthesizer (Scicos Diagram)
• synthe_int - Integrated diagram of an integer-N frequency synthesizer (Scicos Diagram)
• synthe_interp - Scattered diagram of a third order integer-N frequency synthesizer with an interpolated nonlinearity of VCO and with dual-modulus feedback divider (Scicos Diagram)

Authors

A. Layec