MATLAB: How to find sum of square sine wave

MATLABseries sumsquare wave

Hi every one; I want to solve that question.Any assistance will be highly appreciable… function called s_wave that computes the sum for each of 1001 values of t uniformly spaced from 0 to 4π inclusive. The input argument is a positive scalar integer n, and the output argument is a row vector of 1001 such sums—one sum for each value of t. You can test your function by calling it with n == 200 or greater and plotting the result, and you will see why the function is called “s_wave”.

Again any assistance will be highly appreciable…………….

Best Answer

Alright, it looks like you need a lot more help than the hints I gave in my other answer. Here is one way to do it (Put all code in both functions into a single "test.m" and run it):

function test
fontSize = 24;
n = 200;
theSum = s_wave(n);
plot(theSum, 'b-', 'LineWidth', 2);
% Fancy up the plot.
grid on;
caption = sprintf('s_wave : Sum of %d terms', n);
title(caption, 'FontSize', fontSize, 'Interpreter', 'none');
xlabel('t', 'FontSize', fontSize);
ylabel('theSum', 'FontSize', fontSize);
% Enlarge figure to full screen.
set(gcf, 'Units', 'Normalized', 'OuterPosition', [0 0 1 1]);
% Give a name to the title bar.
set(gcf, 'Name', 'Demo by ImageAnalyst', 'NumberTitle', 'Off') 
%============================================================
function theSum = s_wave(n)
t = linspace(0, 4*pi, 1001);
for tIndex = 1 : length(t)
  this_t = t(tIndex);
  k = 1 : n;
  numerator = sin(this_t * (2*k-1));
  denominator = 2 * k - 1;
  theSum(tIndex) = sum(numerator ./ denominator);
end

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MATLAB: How to make a square wave using Fourier synthesis

Try this:

clc;    % Clear the command window.
close all;  % Close all figures (except those of imtool.)
workspace;  % Make sure the workspace panel is showing.
format long g;
format compact;
fontSize = 20;
t=0:0.01:3;
omega = 2*pi;
f = zeros(1, length(t));
for n = 1 : 2 : 201
  f = f + (4/pi) .* 1 ./ n * sin(n * omega * t);
end
plot(t, f, 'b*-', 'LineWidth', 2, 'MarkerSize', 10);
grid on;
xlabel('t', 'fontSize', fontSize);
ylabel('f', 'fontSize', fontSize);
title('Square Wave Approimation', 'fontSize', fontSize);
% Set up figure properties:
% Enlarge figure to full screen.
set(gcf, 'Units', 'Normalized', 'OuterPosition', [0 0 1 1]);
% Get rid of tool bar and pulldown menus that are along top of figure.
set(gcf, 'Toolbar', 'none', 'Menu', 'none');
% Give a name to the title bar.
set(gcf, 'Name', 'Demo by ImageAnalyst', 'NumberTitle', 'Off')

MATLAB: *** Write a function called triangle_wave that computes the sum (−1) sin(2 +1) (2 +1) for each of 1001 values of t uniformly spaced from 0 to 4π inclusive. The input argument is a scalar non-negative integer n, and the output argument is a row v

denominator = (2 * k + 1) .^ 2;

Use the elemtnwise .^ instead of the matrix operation ^ . The same for "(-1)^k" .

The corresponding error message is clear:

 Error using  ^ 
 Inputs must be a scalar and a square matrix.
 To compute elementwise POWER, use POWER (.^) instead.

[EDITED] The formula contains: "Sum from k=0 to n", you code contains:

k = 1:n;

Replace this by k = 0:n. It will be more efficient to move the definition before the loop and pre-allocate the output:

function S = triangle_wave(n)                                      
t = linspace(0, 4*pi, 1001);
S = zeros(size(t));   % Pre-allocation
k = 0:n;              % Not 1:n
for tIndex = 1 : length(t) 
  numerator   = ((-1) .^ k) .* sin(t(tIndex) .* (2 * k + 1));
  denominator = (2 .* k + 1) .^ 2;
  S(tIndex)   = sum(numerator ./ denominator);
end

Best Answer

Related Solutions

MATLAB: How to make a square wave using Fourier synthesis

MATLAB: *** Write a function called triangle_wave that computes the sum (−1) sin(2 +1) (2 +1) for each of 1001 values of t uniformly spaced from 0 to 4π inclusive. The input argument is a scalar non-negative integer n, and the output argument is a row v

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