Matrix dimensions and unbalanced bracket problem

So I have an electrical signal that is given in this form

I'm trying to execute this script in MATLAB to show it visually

function u=sign_sd(t)

% signal
u = [-0.5*t*10e6 * t((t>=0)&(t<=2e-6)),...
    -cos[(pi*10e6*(t-2*10e-6))] * t((t>2)&(t<=4e-6)),...    
    1 * t((t>4)&(t<=6e-6)),...
    0 * t((t>6)&(t<=8e-6)),...
    0 * t(t>8e-6)];

.

% signal graph
t=0:1e6:10e6;
u=sign_sd(t);
plot(t,u),grid on

But any way I try to change it, it gives an error.

Error: File: sign_sd.m Line: 5 Column: 9
Unbalanced or unexpected parenthesis or bracket.

Error in sign_g (line 3)
u=sign_sd(t);

.

size(t) =  1    11
size(u) = 1    21

Currently besides unbalanced matrix dimensions problem there are unbalanced brackets. Possibly where -cos starts. Can any give an advice on how to fix it, so it works? I've also tried to use zeros(size(t)) in '% signal graph' code, but that didn't solve it.

[madhan ravi]

Try to remove the square brackets only for cos.

Answer 1

[Rik]

Here's a complete plot. You also forgot to put in extra exponents for the lower bounds.

%t=0:1e-6:10e-6;
t=linspace(0,10e-6,200);
figure(1),clf(1)
plot(t,sign_sd(t))
axis tight
ax = gca;
ax.XAxis.Exponent = -6;

function u=sign_sd(t_master)
u=NaN(size(t_master));
L=(t_master>=0)&(t_master<=2e-6);
t=t_master(L);
u(L)=-0.5*t*10^6;
L=(t_master>2e-6)&(t_master<=4e-6);
t=t_master(L);
u(L)=-cos(pi*10e6*(t-2*10e-6));
L=(t_master>4e-6)&(t_master<=6e-6);
u(L)=1;
L=(t_master>6e-6)&(t_master<=8e-6);
u(L)=0;
L=t_master>8e-6;
u(L)=0;
end

[jeff m]

Thank you, this works.

Answer 2

[Titus Edelhofer]

Hi Jeff,

I would rather use indexing instead of multiplication, something like

u = zeros(size(t));

% first 2 microseconds:
idx = t>=0 & t<=2e-6;
u(idx) = -0.5 * t(idx) * 1e6;

etc.

Titus

[jeff m]

Thanks.