MATLAB Answers

MATLAB is not plotting my constant value plot. Why so?

clc
close all
clear
bw=100e3;
FS=2e-9;
IBQN_dBFS=-76.1;
P_IBN=(10^(IBQN_dBFS/10))*(0.5*((FS/2)^2));
PSDnin1=sqrt((P_IBN)/(bw));
figure(1)
plot(linspace(0,bw,10),PSDnin1)
% loglog(linspace(0,bw,10),PSDnin1)
xlabel('Frequency(Hz)')
ylabel('PSDin(A2/Hz)')
axis auto
This is my matlab code and i would like to plot the constant value of PSDnin = 3.5e-15 as a constant line from 0 to bw. I get an empty graph.
Is it plotting and I am unale to see?
Is it because of the lower value? I tried the loglog plot. But it doesnt help. Please help me to resolve the issue.

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R2017a

1 Answer

Answer by Jan
on 29 May 2019
Edited by Jan
on 29 May 2019
 Accepted Answer

The code does draw some points. You see them, if you use a marker:
plot(linspace(0,bw,10), PSDnin1, 'o')
or with a line:
plot(linspace(0,bw,10), repmat(PSDnin1, 1, 10))
The documentation of plot mentions:
If one of X or Y is a scalar and the other is either a scalar or a vector, then the plot function plots discrete points. However, to see the points you must specify a marker symbol, for example, plot(X,Y,'o').

  1 Comment

Hey Jan,
Yes that worked. Great!!.
This one also worked giving a straight line
semilogy([0,bw],[PSDnin1,PSDnin1])
or
plot([0,bw],[PSDnin1,PSDnin1])
Thanks a lot

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