20191112 telecoms lab2

>> f1 = [-2.5:0.001:2.5];
>> y1=4*sinc(2*f1).^2-(sinc(f1)).^2;
Undefined function 'sinc' for input arguments of
type 'double'.

Did you mean:
>> y1=4*(sin(pi*2*f1)/(pi*2*f1)).^2-(sin(pi*f1)/(pi*f1)).^2;
>> t = [-4:0.2:4];
>> y2 = [zeros(1,10), [0:0.2:1], ones(1,9), [1:-0.2:0], zeros(1,10)];
>> subplot(211);
>> plot(f1, abs(y1));
>> subplot(212);
>> plot(t, y2);
>> y1=4*(sin(pi*2*f1)./(pi*2*f1)).^2-(sin(pi*f1)./(pi*f1)).^2;
>> subplot(211);
>> plot(f1, abs(y1));