discrete-time real exponential signal
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HOW CAN I DELETE THOSE POINTS WHICH ARE VISIBLE AT ZERO AT COUPLE TIMES?
I was trying to create a power signal as
with α = -0.9 between -10 < t < 10
![](https://www.mathworks.com/matlabcentral/answers/uploaded_files/810359/image.png)
Here is the graph which I was trying to achieve:
![](https://www.mathworks.com/matlabcentral/answers/uploaded_files/810344/image.png)
clc; clear; close all
alpha = -.9;
t = -10 : 0.5 : 10;
y = power(alpha, t);
stem(t,y, '- b',...
'LineWidth',2);
title ('\bf\it 3rd QUESTION ', 'fontsize', (25));
xlabel ('\bf INPUT ', 'fontsize', (20));
ylabel ('\bf OUTPUT ', 'fontsize', (20));
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Accepted Answer
Paul
on 24 Nov 2021
Those points at zero show up because alpha is negative and the code is raising alpha to non-integer powers t. For those values of t, alpha^t is complex, and they all have real part equal 0 for those values of t. For example
alpha = -.9;
power(alpha,-9.5)
Then, as the warning states, stem() plots the real part, which is why those zero points show up.
The solution is to only define t with integer values
t = -10 : 1 : 10;
y = power(alpha, t);
stem(t,y, '- b','LineWidth',2);
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