1 files changed, 50 insertions, 0 deletions
diff --git a/339/CH9/EX9.13/ex9_13.sce b/339/CH9/EX9.13/ex9_13.sce
new file mode 100755
index 000000000..4ef7d55bd
--- /dev/null
+++ b/339/CH9/EX9.13/ex9_13.sce
@@ -0,0 +1,50 @@
+//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);
+
+K=1.18
+
+//find the maximum gain
+Gmax=abs(s21/s12)*(K-sqrt(K^2-1));
+Gmax_dB=10*log10(Gmax)
+
+//specify the target gain
+G_goal_dB=8; //would like to build an amplifier with 8dB gain
+G_goal=10^(G_goal_dB/10); //convert from dB to normal units
+
+//find constant operating power gain circles
+go=G_goal/abs(s21)^2;
+
+//find the center of the constant operating power gain circle
+dgo=go*conj(s22-conj(s11))/(1+go*(abs(s22)^2));
+
+
+//find the radius of the circle 
+rgo1=sqrt(1-2*K*go*abs(s12*s21)+go^2*abs(s12*s21)^2);
+rgo=rgo1/abs(1+go*(abs(s22)^2));
+
+//plot a circle in the Smith Chart
+a=(0:360)/180*%pi;
+
+set(gca(),"auto_clear","off");
+plot(real(dgo)+rgo*cos(a),imag(dgo)+rgo*sin(a),'r','linewidth',2);
+
+//choose the load reflection coefficient
+zL=1-%i*0.53
+GL=(zL-1)/(zL+1);
+
+plot(real(GL),imag(GL),'bo');
+
+[Ro,Theta]=polar(atan(imag(Gs),real(Gs)));
+Gin=s11+s12*s21*GL/(1-s22*GL);
+Gs=conj(Gin);
+Gs_abs=abs(Gs)
+Gs_angle=(Theta/%pi)*180;
+
+zs=(1+Gs)/(1-Gs);
+
+
+
+