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.2 MatLab
rectpuls .
y = rectpuls (t, w)
, w, t=0 t . w , . , ,
t = 0: 0.01: 10;
y = 0.75*rectpuls(t-3, 2)+0.5*rectpuls(t-8, 0.4)+1.35*rectpuls(t-5, 0.8);
Plot(t,y)
pulstran (. MatLab).
.3
fft. fft , , , :
- Ts Fmax ( ) :
Fmax = 1/Ts;
- df :
df =1/T;
- , -.
( ) :
f1=0: df: Fmax.
fft . ifft, , .
- fft fftshift, ;
-
f = -Fmax/2: df: Fmax/2.
-
, .
Ts=0.01, =100, =0.75 w=0.5:
Ts=0.01; T=100; A=0.75; w=0.5; t=0: Ts: T;
y = A*rectpuls(t, w);
plot(t(1:100),y(1:100)),
y fft . stem:
x=fft(y); df=1/T; Fmax=1/Ts; f=0: df: Fmax; a=abs(x);
Stem(f,a),
- :
xp=fftshift(x); f1=-Fmax/2: df: Fmax/2; a=abs(xp);
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Stem(f1,a)