1 files changed, 12 insertions, 0 deletions
diff --git a/40/CH9/EX9.5/Exa_9_5.sce b/40/CH9/EX9.5/Exa_9_5.sce
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+//Mappings from difference algorithms
+//Backward difference mappings
+s=%s;z=%z;
+ts=1;a=1;
+HS=1/(s+a);
+HZa=horner(HS,(z-1)/(z*ts))
+z1=roots(denom(HZa))//for ts >0 HZa always stable
+HZb=horner(HS,(z-1)/ts)
+z2=roots(denom(HZb))//stable only for 0<ats<2
+HZc=horner(HS,(z^2-1)/(2*z*ts))
+z3=roots(denom(HZc))//magnitude of 1 pole is always>1 hence unstable
+