数字信号基于matlab模拟窗函数频谱细化【含Matlab源码 1906期】.zip

clear; close all; clc; N=50; w=boxcar(N); W=fft(w,256); figure(1) subplot(2,1,1); stem([0:N-1],w); subplot(2,1,2); plot([-128:127],abs(fftshift(W))) N=input('窗函数长度='); L=512; f1=100;f2=120;fs=600; ws=2*pi*fs; t=(0:N-1)*(1/fs); x=cos(2*pi*f1*t)+cos(2*pi*f2*t); figure(2) subplot(211);stem(t,x); W=fft(x,L); f=((-L/2:L/2-1)*(2*pi/L)*fs)/(2*pi);% f=((-L/2:L/2-1)*(1/L)*fs); subplot(212); plot(f,abs(fftshift(W))) L=512; f1=100;f2=120;fs=600; ws=2*pi*fs; t=(0:N-1)*(1/fs); x=cos(2*pi*f1*t)+cos(2*pi*f2*t); wh=hamming(N)'; x=x.*wh; figure(3) subplot(211);stem(t,x); W=fft(x,L); f=((-L/2:L/2-1)*(2*pi/L)*fs)/(2*pi); subplot(212); plot(f,abs(fftshift(W))) L=512; f1=100;f2=150;fs=600; ws=2*pi*fs; t=(0:N-1)*(1/fs); x=cos(2*pi*f1*t)+0.15*cos(2*pi*f2*t); figure(4) subplot(211);stem(t,x); W=fft(x,L); f=((-L/2:L/2-1)*(2*pi/L)*fs)/(2*pi); subplot(212); plot(f,abs(fftshift(W))) L=512; f1=100;f2=150;fs=600; ws=2*pi*fs; t=(0:N-1)*(1/fs); x=cos(2*pi*f1*t)+0.15*cos(2*pi*f2*t); wh=hamming(N)'; x=x.*wh; figure(5) subplot(211);stem(t,x); W=fft(x,L); f=((-L/2:L/2-1)*(2*pi/L)*fs)/(2*pi); subplot(212); plot(f,abs(fftshift(W)))