Question

有一连续信号x(t)=sin2πft,其中f=8khz,如果时域取样频率fs=4f;

Answer 1

n=0:1:1023;

>> t=1/4.*n;

>> x=sin(2*pi*t); %采样后的离散信号

>> X=fft(x,1024); %做fft变换

>> X1=dft(x,1024); %做dft变换

>> magX1=abs(X1); %振幅谱

>> phaX1=angle(X1)*180/pi; %相位谱

做之前,在file中建一个M-file

function [Xk]=dft(xn,N)

%Computes Discrete fouriwe transform

%----------------------------------

%[Xk]=dft(xn,N)

%Xk=DFT coeff.array over 0