remove zeros from sinc function

Question

Gaurav Sharma 2019-5-17

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/462570-remove-zeros-from-sinc-function

回答： Sulaymon Eshkabilov 2019-5-18

Hi there,

I am trying to observe the behaviour of the fourier trasform of the sinc function if some of its zeros will be removed. Normally, the sinc function will lead us to rectanglular function in fourier domain, but when I am trying to remove the zeros at 'pi' it is not showing anything due to NaN or infinite. May I request you to pls tell me how to deal with such problem?

Fs=42;Ts=1/Fs;
t=-1:Ts:40*Ts-Ts;
f=5;
y=sinc(t*f)/(1-5*t/(0.9)*pi);
figure;
plot(t,y);
xlabel('x');
ylabel(' magnitude');
fy=fft(y);%figure;
% plot(fy)
fy = fftshift(fy);figure;
plot([abs(fy)])%;angle(fy);real(fy);imag(fy)]','*')

2 个评论
显示无隐藏无

Jan 2019-5-17

编辑：Jan 2019-5-17

It is easier to read, if you include the code directly. Therefore I've copied it from the attachment.

"it is not showing anything due to NaN or infinite" - what is "it" here?

Gaurav Sharma 2019-5-18

"the plot"- is not showing any thing... no plot.... just blank screen

请先登录，再进行评论。

请先登录，再回答此问题。

Answer 1

Sulaymon Eshkabilov 2019-5-18

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/462570-remove-zeros-from-sinc-function#answer_375583

在 MATLAB Online 中打开

clearvars; close all
Fs=42;Ts=1/Fs;
t=-1:Ts:1;
f=5;
y=sinc(t*f)./(1-5*t/(0.9)*pi);
figure;
plot(t,y), xlabel('t'), ylabel(' y(t)'); title('Time domain analysis ')
L = length(t); Nblock = 256;
Y = fft(y, Nblock)/L;
f = Fs/2*linspace(0,2, Nblock/2+1);
figure;
plot(f, 2*abs(Y(1:Nblock/2+1))), title('Discrete FFT')
fY = fftshift(Y);figure;
plot(f, 2*abs(fY(1:Nblock/2+1))), title('Shift zero frequency') 
figure, plot([angle(fY);real(fY);imag(fY)]','*') 
title('Phase angle, Real & Imag components of Shift zero frequency')