plotting a multiple output function

Hello!

I am quite new at Matlab

I have tried to plot a multiple output function but all i got is the first out put.

this is the code :

function [h, H] = myrct (t,f,beta)

% In optical communication systems, different linear pulse-shaping filters

% are used to generate continuous-time transmit signals. We can define

% these filters either through their impulse response hp(t) or their

% frequency response Hp( f )=F{hp(t)}, where F{ } stands for the Fourier

% transform.

% rct: Raised-cosine time domain (RCT-Filter)

% Time Domain

h = (1 + cos((pi./beta).*(abs(t)-(1-beta)/2)))/2;

h(abs(t)>(1+beta)/2) = 0;

h(abs(t)<(1-beta)/2) = 1;

h(abs(t)==1/2) = 1/2;

% Frequency Domain

% H = fftshift(fft(h),1);

H = sinc(f).*cos(pi.*beta.*f)./(1-(2*beta.*f).^2);

H(f == -0.5/beta) = sinc(1/(2*beta))*pi/4 ;

H(f == +0.5/beta) = sinc(1/(2*beta))*pi/4;

end

I tried to use :

figure

plot(myrct(t,f,beta))

hold on

It doesn't work and it plots only the first output 'h'.

i tried also

figure

plot(H)

hold on

but I got a msg of Unrecognized function or variable 'h'.

Here are the constants:

l=randi(50,1)

N=randi(50,1)

t=(-l*N/2:l*N/2-1)'/N;

f=(-l*N/2:l*N/2-1)'/l;

beta=rand(1)

please help me with this

Answer 1

[Geoff Hayes]

Moussa - rather than trying to calculate and plot the results of the myrct in one like like

plot(myrct(t,f,beta))

split this into two lines to make clear what the outputs are for myrct. Try

[h, H] = myrct(t,f,beta);
figure;
plot(h);
hold on;
plot(H);

or however you want to do this. If I recall correctly, if you just call the function without specifying the output parameters like

[h, H] = myrct(t,f,beta);

then myrct(t,f,beta) will just return the first output parameter, the h. Note also that you need to explicilty set the output parameters in order to be able to reference them. We do that with the above line of code. When you don't do that and then try to reference (later) h or H you will get an error like you mentioned above Unrecognized function or variable 'h'.

[Moussa Ihab]

Thank you

it works very well