N = 4; %400; % number of pulses
Tp = 1; % pulse width;
d1 = 1; % interphase delay
d2 = 1; % interpulse delay [us]).
U0 = 1;
% define sampling freq
fs = 10; % MHz (time in us)
% single pulse
x1 = [ ones(round(Tp*fs), 1) % +ve pulse
zeros(round(d1*fs), 1) % d1
-ones(round(Tp*fs), 1) % -ve pulse
zeros(round(d2*fs), 1)]; % d2
x = U0*repmat(x1, N, 1);
t = (0:length(x)-1)/fs;
stairs(t, x);
grid on
ylim([-1 1]*1.5*U0)
