# Plotting more than one DTMF frequencies on a graph

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kyin gab am 25 Nov. 2012
Kommentiert: Yusra Banday am 26 Apr. 2023
Hello,
I can plot single dtmf frequency. I would like to plot more than one frequency on a single graph. How do I do it?
Exampl below:
t = 0:1/32798:0.25-1/32798; x = sin(2*pi*xxx*t) + sin(2*pi*yyy*t);
x2 = sin(2*pi*aaa*t2) + sin(2*pi*bbb*t2);
if I do
plot(t, x); title('DTMF Signal for t = 0.25s'); xlabel('time (s)'); ylabel('Amplitude');
it will plot x for me.
Now I would like to plot x and x2 on the same graph. I am aware of putting frequency of zero in between.
Thank you.
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Jonathan Epperl am 25 Nov. 2012
It's not clear to me, what exactly you are asking. Are you asking how to put more than one line in a plot? If so, either
plot(t,x,'b',t2,x2,'k');
or
plot(t,x);
hold on
plot(t2,x2);
hold off
doc plot
kyin gab am 25 Nov. 2012
I may not be clear enough.
I have two signal gotten from a keypad (number 2 and 7);
t = 0:1/32798:0.25-1/32798;
x2 = sin(2*pi*1336*t) + sin(2*pi*697*t);
x7 = sin(2*pi*1209*t) + sin(2*pi*852*t);
I want to plot these two signals in one graph. I am finding it difficult to do it. I want the graph to look like the last one on page 2 of this www.engr.mun.ca/~sircar/project1_files/dtmf.pdf
I am aware that I have to add a silence period between.
Thank you.

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### Akzeptierte Antwort

Jonathan Epperl am 25 Nov. 2012
Okay, now that your question is clearer to me, I think this is what you want:
t = 0:1/32798:0.25-1/32798;
x2 = sin(2*pi*1336*t) + sin(2*pi*697*t);
x7 = sin(2*pi*1209*t) + sin(2*pi*852*t);
int_of_silence = .1; shift = t(end)+ int_of_silence;
plot(t, x2, 'b', t+shift, x7, 'b', [t(end) t(end)+int_of_silence], [0 0], 'b', t+2*shift, x2, 'b', 2*[t(end) t(end)+int_of_silence], [0 0], 'b')
You see the trick is shifting the time axis for each segment by the right amount, I called it shift. The [t(end) t(end)+int_of_silence], [0 0], 'b' part is only to draw a line at 0 between segments.
##### 3 Kommentare1 älteren Kommentar anzeigen1 älteren Kommentar ausblenden
JAFARU IBRAHIM am 8 Nov. 2017
Hi, Thank you very much (both of you),
I really found this question very important and related to my problem, so please Jonathan or Kyarn, how can you play the sound of the signal above, then? Tanx
Yusra Banday am 26 Apr. 2023
now if we have to plot all the12 tones on a same graph.We can use subplot but graphs cant still be hold.so how can v get all graphs plotted on same fig??

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