# Nyquist Plot vs. Complex Function Plot

Gold Member
This is not a homework problem, I just am confused a little about the differences between a Nyquist plot and the plot of a complex function. I believe they are the same given the domain of the plot of a complex function is for all real numbers equal to or greater than zero. However, I am having a hard time demonstrating this. So what is the difference? Is there a difference?

My original goal was to get a geometric understanding of complex functions and seeing the difference between differential complex functions and non-differential complex functions. What programs can I use to get a geometric understanding of complex functions.

I'm using matlab, but I am open to any suggestions. My code is below and I'm trying to plot the transfer function 50/(s+3) with a nyquist function, and a scatter plot. I expected that the scatter plot was going to make the same shape as the nyquist function, but it doesn't. Any suggestions?

Code:
y=-10:0.001:10;
x=0:0.001:20;
z=x'*ones(1,length(y))+ones(1,length(x))'*1i*y;
fz=50*(z+3)\ones(length(z));
scatter(real(fz(:)),imag(fz(:)))
figure
nyquist(zpk([],[-3],50))

Thanks for checking this out!!

• 