3/25/08
more z transform stuff
quiz on thursday 27th
z transform properties on 11.2
assume f[n]u[n] <=> F[z]
right shift: f[n-m]u[n-m] <> F[z]/(z^m)
	f[n-m]u[n] <> F[z]/(z^m) + (z^-m)sum<n=1,m>(f[-n]z^n)
left:	"  +         "(z^m)F[z]  - "  +        0,m-1  +    -n"
mult by gamma^n	F[z/gamma]
mult by n, 	-zF'[z] 

solve difference equations w/ ZT (Fig1)
another example (Fig2)