1 files changed, 65 insertions, 0 deletions
diff --git a/339/CH9/EX9.14/ex9_14.sce b/339/CH9/EX9.14/ex9_14.sce
new file mode 100755
index 000000000..0b6e65f6a
--- /dev/null
+++ b/339/CH9/EX9.14/ex9_14.sce
@@ -0,0 +1,65 @@
+global Z0;
+Z0=50;
+
+//define the S-parameters of the transistor
+s11=0.3*exp(%i*(+30)/180*%pi);
+s12=0.2*exp(%i*(-60)/180*%pi);
+s21=2.5*exp(%i*(-80)/180*%pi);
+s22=0.2*exp(%i*(-15)/180*%pi);
+
+//pick the noise parameters of the transistor
+Fmin_dB=1.5
+Fmin=10^(Fmin_dB/10);
+Rn=4;
+Gopt=0.5*exp(%i*45/180*%pi);
+
+//compute a noise circle
+Fk_dB=1.6;
+Fk=10^(Fk_dB/10);
+
+
+Qk=abs(1+Gopt)^2*(Fk-Fmin)/(4*Rn/Z0) //noise circle parameter
+dfk=Gopt/(1+Qk); //circle center location
+rfk=sqrt((1-abs(Gopt)^2)*Qk+Qk^2)/(1+Qk) //circle radius
+ 
+
+//plot a noise circle
+a=[0:360]/180*%pi;
+set(gca(),"auto_clear","off");
+plot(real(dfk)+rfk*cos(a),imag(dfk)+rfk*sin(a),'b','linewidth',2);
+
+// plot optimal reflection coefficient
+plot(real(Gopt),imag(Gopt),'bo');
+
+
+//specify the desired gain
+G_goal_dB=8;
+G_goal=10^(G_goal_dB/10);
+
+//find the constant operating power gain circles
+go=G_goal/abs(s21)^2; // normalized the gain
+dgo=go*conj(s22-conj(s11))/(1+go*(abs(s22)^2)); //center
+
+rgo=sqrt(1-2*K*go*abs(s12*s21)+go^2*abs(s12*s21)^2);
+rgo=rgo/abs(1+go*(abs(s22)^2));
+
+//map a constant gain circle into the Gs plane
+rgs=rgo*abs(s12*s21/(abs(1-s22*dgo)^2-rgo^2*abs(s22)^2));
+dgs=((1-s22*dgo)*conj(s11-dgo)-rgo^2*s22)/(abs(1-s22*dgo)^2-rgo^2*abs(s22)^2);
+
+//plot a constant gain circle in the Smith Chart
+set(gca(),"auto_clear","off");
+plot(real(dgs)+rgs*cos(a),imag(dgs)+rgs*sin(a),'r','linewidth',2);
+
+
+
+//choose a source reflection coefficient Gs
+Gs=dgs+%i*rgs;
+plot(real(Gs), imag(Gs), 'ro');
+//text(real(Gs)-0.05,imag(Gs)+0.08,'\bf\Gamma_S');
+
+//find the actual noise figure
+F=Fmin+4*Rn/Z0*abs(Gs-Gopt)^2/(1-abs(Gs)^2)/abs(1+Gopt)^2;
+
+//print out the actual noise figure
+Actual_F_dB=10*log10(F)
+\ No newline at end of file