Question

Need help with coding in MATLAB for communication

1. Use DFT to find the magnitude and phase spectra of the periodic triangular pulses where has a peak value of 3 at. It is symmetric about with the end points at . The period of is 5. a) Plot for b) Plot the magnitude and phase spectra of.

Answer 1

TO FIND DFT & IDFT OF A GIVEN SIGNAL USING INBUILT MATLAB FUNCTION:

clc

clear all

close all

x=input('enter the sequence of x')

N=input('length of dft N=')

disp('N-point DFT')

X=fft(x)

n=0:1:length(X)-1

subplot(2,2,1)

stem(n,x)

xlabel('time')

ylabel('amplitude')

title('input sequence')

subplot(2,2,2)

stem(n,abs(X))

xlabel('frequency')

ylabel('amplitude')

title('magnitude spectrum of x[n]')

subplot(2,2,3)

stem(n,angle(X))

xlabel('frequency')

ylabel('phase')

title('phase spectrum of x[n]')

%inverse DFT

disp('N-point IDFT')

xr= ifft(X)

subplot(2,2,4)

stem(n,xr)

xlabel('time')

ylabel('amplitude')

title('IDFT')

THIS IS THE CODE FOR ANY SEQUENCE

if u wanna plot for triangular pulse

use syms

code:

syms x

fplot(triangularPulse(x,[-a a]))

SAMPLE INPUTS:

X = [ [2,3,-8,-6,4,1,-9]]

Xr= [2.000000000000000,3,-8,-6,4,1,-9]

N-point DFT

X =

  Columns 1 through 5

-13.0000 + 0.0000i   1.6186 + 3.7312i   8.3949 -23.4224i   3.4864 - 2.4938i   3.4864 + 2.4938i

Columns 6 through 7

   8.3949 +23.4224i   1.6186 - 3.7312i