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luccasrodrigo
luccasrodrigo
2:01 AM
Hello @slca
ty...
I do not know where to start with matlab = \
by the way
 
slca
slca
Ok
 
luccasrodrigo
luccasrodrigo
I managed to plot this graph
Fi = 2500;
Fs = 48e3;
N = 1024;
x = sin(2*pi*Fi/Fs*(1:N)) + 0.001*randn(1,N);
SNR = snr(x,Fs)
and → snr(x,Fs);
But what can I do for my case?
 
slca
slca
Are you looking to plot the SNR of the plots you showed in your question?
 
luccasrodrigo
luccasrodrigo
yep
But I do not know how to do it...
 
slca
slca
From the plots, you can see the amplitudes at specific times
 
luccasrodrigo
luccasrodrigo
2:06 AM
right
how am I going to draw the noise waves?
are many points
 
slca
slca
So you can create a vector, say t = [t1, t2, t3,...,tn], t1, t2, t3 are just the times you see in both plot b and c
Well, you don't have a choice if those are the graphs you are given
You don't need all the points, choose a number of them, I don't know what else to tell you, that's what I would do
Also create a vector signal and a vector noise. Those need to have the same number of points as t
The signal vector comes from plot b. Choose the amplitudes corresponding to the times in t. Same for plot c, that is the noise vector
 
luccasrodrigo
luccasrodrigo
How do I create this vector of points for the signal and noise? And then plot in MATLAB?
I'm an amateur with matlab ...
I know few features ...
 
slca
slca
And find SNR = 20 log(signal./noise)
 
luccasrodrigo
luccasrodrigo
SNR and graph are not one of them
 
slca
slca
I don't know what you need then
What is that you need to plot?
 
luccasrodrigo
luccasrodrigo
2:13 AM
Find the SNR, so I do not know how to do this in MATLAB ...
 
slca
slca
That's what I am explaining to you
It's math. Take the x,y coordinates on plots b and c
 
luccasrodrigo
luccasrodrigo
Sorry for my ignorance, but if you could "take my hand" to program, if you understand me ...
What should I write exactly on the matlab screen...
do you use any software for remote access?
 
slca
slca
This is what I would do.
t = [t1,t2,t3,t4,t5,t6];
signal = [s1,s2,s3,s4,s5,s6];
noise = [n1,n2,n3,n4,n5,n6];

snr = 20*log10(signal./noise);
plot(t,snr)
 
luccasrodrigo
luccasrodrigo
I do not know how to plot this vector in matlab using the coordinates x and y
AAAAH,
Ok just a moment ♥
 
slca
slca
You may need to rename, snr to maybe SNR, since there is a function called snr in matlab
That's just an example, with 6 points, you can use as many as you need
 
luccasrodrigo
luccasrodrigo
2:21 AM
"t" stands for what exactly?
 
slca
slca
But like I said, that's how I would do that if I am given a plot like yours and I have no way to extract the points with matlab
t is time
 
luccasrodrigo
luccasrodrigo
@slca ooh, OK
@slca Okay, but that's right.
I'll try,
 
slca
slca
I hope it helps
 

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