How do you create a biphasic rectangular signal?

hi, i want to create a biphasic rectangular signal with amplitude of 1, duty cycle of 25%, frequency of 3Hz, is there a matlab function for this?

i can easily make the rectangular train pulse but im struggling with this

it should be looking like this:

Answer 1

[Dave B]

If you have access to signal processing toolbox you can do this with pulstrain

I'm sure there's a cleaner/clearer way to use this but here's what I worked out for an arbitrary width and frequency. Note that each pulse has a time and amplitude, you can make the amplitude +/-1 to achieve a biphasic pulse.

t=linspace(0,1,1000);
w = .02;

dPos = .1:.1:1;
dNeg = dPos + w;
dT = [dPos dNeg]';
dAmp = [ones(numel(dPos),1); -1 * ones(numel(dNeg),1)];

y = pulstran(t,[dT dAmp],'rectpuls',w);
plot(t,y)
ylim padded

[miroslava del carmen villanueva castillo]

so if i wanted to make any function biphasic like lets say a sine function, i could place the funtion into the pulstran right? but how would you place the parameters?

[miroslava del carmen villanueva castillo]

i tried to do something like this but it did not work out

Y = pulstran(T,D,sin(4*pi*f*t));

[Dave B]

This would look a little more like

y=pulstran(T,D,@(x)sin(x*2*pi))

Otherwise MATLAB is just going to evaluate the sin() and treat that argument like the numeric result.

There's a more detailed example of a custom function on the pulstrain documentation page and some general strategies for passing extra function parameters here.

[miroslava del carmen villanueva castillo]

thank you!!!