【信号与系统 x MATLAB】实验一

信号与系统实验（一）

clear

利用MATLAB实现下列信号，并绘出图形

f = @(t) stepfun(2*t,0)

f = 包含以下值的 function_handle: @(t)stepfun(2*t,0)

fplot(@(t)f(t),[-10,10])

f = @(t) 4.*exp(-2.*t).*cos(pi.*t)

f = 包含以下值的 function_handle: @(t)4.*exp(-2.*t).*cos(pi.*t)

fplot(@(t)f(t),[0,10])

f3 = @(t) stepfun(t,-1) - stepfun(t,1) + stepfun(t,-3) - stepfun(t,3)

f3 = 包含以下值的 function_handle: @(t)stepfun(t,-1)-stepfun(t,1)+stepfun(t,-3)-stepfun(t,3)

fplot(@(t)f3(t),[-10,10])

f = @(k) stepfun(k,-3) - stepfun(k,2)

f = 包含以下值的 function_handle: @(k)stepfun(k,-3)-stepfun(k,2)

stem(-10:10,f(-10:10))

f = @(k) 5.*(0.4).^k.*cos(1.2.*pi.*k)

f = 包含以下值的 function_handle: @(k)5.*(0.4).^k.*cos(1.2.*pi.*k)

stem(-10:10,f(-10:10))

f = @(t) 2.*sin(t./2)./t

f = 包含以下值的 function_handle: @(t)2.*sin(t./2)./t

fplot(@(t)f(t),[-10,10])

fplot(@(t)f3(0.5.*t),[-10,10]) %1

T = -10:0.1:10;

F = arrayfun(@(t)f3(2-2.*t),T);

plot(T,F) %2

df3 = diff(F);

plot(-10:0.1:10-0.1,df3) %3

T = 0:0.01:10;

plot(T,ff(T,1))

hold on

plot(T,ff(T,2))

plot(T,ff(T,200))

hold off

legend("n=1","n=2","n=200")

function s = ff(t,k)
s = zeros(1,length(t));
    for i = 1:k
        s = s + sin((2.*i-1).*t)./(2.*i-1);
    end
end