Time between excitation wave and received waves

If I have graph of voltage vs time for the excitation signal and the received signal for a material...how do I calculate the time it takes for the wave to move from one side of the material to the other side.. the blue signal is the excitation then the orange signal is the received one

[Jonas]

can you provide an image or data so we can see the excitation signal and the resulting signal?

[LINDO MTSWENI]

attached is the figure ... thye blue signal is the excitation then the orange one is the received signal

Answer 1

[Star Strider]

Try this —

F = openfig('sample.fig');
Ax = gca;
Lines = findobj(Ax, 'Type','line')

sent = findobj(Lines,'DisplayName','Excitation Signal');
Xsent = sent.XData;
Ysent = sent.YData;

recd = findobj(Lines,'DisplayName','Received Signal');
Xrecd = recd.XData;
Yrecd = recd.YData;

Ysidx = Ysent>0.01;                                                 % Threshold Signal
Yridx = Yrecd>0.01;                                                 % Threshold Signal

Yss = find(Ysidx,1,'first');                                        % First 'true' Index
Yrs = find(Yridx,1,'first');                                        % First 'true' Index

[istart,istop,dist] = findsignal(Yrecd(Yridx), Ysent(Ysidx));

figure
findsignal(Yrecd(Yridx), Ysent(Ysidx))
grid

figure
subplot(2,1,1)
plot(Xsent, Ysent)
% text(Xsent([istart istop])+Xsent(Yss), [0 0], compose('\\leftarrow t = %8.5E', Xsent([istart istop])+Xsent(Yss)), 'Rotation',90)
title('Sent')
grid
subplot(2,1,2)
plot(Xrecd, Yrecd)
text(Xrecd([istart istop])+Xrecd(Yrs), [0 0], compose('\\leftarrow t = %8.5E', Xrecd([istart istop])+Xrecd(Yrs)), 'Rotation',90, 'Horiz','left', 'Vert','middle')
title('Received')
grid

See the documentation on findsignal for details.

.

[LINDO MTSWENI]

Ok thanks, I did that these it gave me these graphs ( attached) .. .. what I actually want is one value ( time ) so that I can calculate the speed of sound through ta certain medium.. if I have the length of the medium then get time from those graphs...I can can calculate the speed of sound though the medium ..

V = t/s ..where t is the thickness and s is the time...

[Star Strider]

The time the incident (‘Excitation Signal’) began is:

SentStartTime = XSent(Yss);

The interval between that and the first ‘Received Signal’ time is:

Delay = Xrecd([istart istop])+Xrecd(Yrs)) - SentStartTime

Those calculations should produce the desired result with respect to the time differences.

The signals in the second image are not the same as the signals provided. Remember to apply an appropriate threshold, because otherwise the time at zero amplitude will be included.

.

[LINDO MTSWENI]

Thanks... it worked

[Star Strider]

As always, my pleasure!