sine wave plot
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Hi,
I am having some trouble plotting a sine wave and i'm not sure where i am going wrong.
i have
t = [0:0.1:2*pi]
a = sin(t);
plot(t,a)
this works by itself, but i want to be able to change the frequency. When i run the same code but make the change
a = sin(2*pi*60*t)
the code returns something bad. What am i doing wrong? How can i generate a sin wave with different frequencies?
14 Comments
Gokul Krishna N
on 13 Oct 2021
Just been reading the comments in this question. Hats off to you, sir @Walter Roberson
Accepted Answer
Rick Rosson
on 24 Apr 2012
Please try:
%%Time specifications:
Fs = 8000; % samples per second
dt = 1/Fs; % seconds per sample
StopTime = 0.25; % seconds
t = (0:dt:StopTime-dt)'; % seconds
%%Sine wave:
Fc = 60; % hertz
x = cos(2*pi*Fc*t);
% Plot the signal versus time:
figure;
plot(t,x);
xlabel('time (in seconds)');
title('Signal versus Time');
zoom xon;
HTH.
Rick
8 Comments
MD RAJIBUL HOSSAIN RUBEL
on 28 May 2021
There are two numbers given as -5+2i 3-2i using Plot and Stem function show the output of this equation
More Answers (12)
Mike Mki
on 29 Nov 2016
Dear Mr. Rick, Is it possible to create knit structure in Matlab as follows:

0 Comments
Robert
on 28 Nov 2017
aaa,
What goes wrong: by multiplying time vector t by 2*pi*60 your discrete step size becomes 0.1*2*pi*60=37.6991. But you need at least two samples per cycle (2*pi) to depict your sine wave. Otherwise you'll get an alias frequency, and in you special case the alias frequency is infinity as you produce a whole multiple of 2*pi as step size, thus your plot never gets its arse off (roundabout) zero.
Using Rick's code you'll be granted enough samples per period.
Best regs
Robert
0 Comments
Junyoung Ahn
on 16 Jun 2020
clear;
clc;
close;
f=60; %frequency [Hz]
t=(0:1/(f*100):1);
a=1; %amplitude [V]
phi=0; %phase
y=a*sin(2*pi*f*t+phi);
plot(t,y)
xlabel('time(s)')
ylabel('amplitude(V)')
0 Comments
shampa das
on 26 Dec 2020
Edited: Walter Roberson
on 31 Jan 2021
clc; t=0:0.01:1; f=1; x=sin(2*pi*f*t); figure(1); plot(t,x);
fs1=2*f; n=-1:0.1:1; y1=sin(2*pi*n*f/fs1); figure(2); stem(n,y1);
fs2=1.2*f; n=-1:0.1:1; y2=sin(2*pi*n*f/fs2); figure(3); stem(n,y2);
fs3=3*f; n=-1:0.1:1; y3=sin(2*pi*n*f/fs3); figure(4); stem(n,y3); figure (5);
subplot(2,2,1); plot(t,x); subplot(2,2,2); plot(n,y1); subplot(2,2,3); plot(n,y2); subplot(2,2,4); plot(n,y3);
0 Comments
soumyendu banerjee
on 1 Nov 2019
%% if Fs= the frequency u want,
x = -pi:0.01:pi;
y=sin(Fs.*x);
plot(y)
0 Comments
wilfred nwakpu
on 1 Feb 2020
%%Time specifications:
Fs = 8000; % samples per second
dt = 1/Fs; % seconds per sample
StopTime = 0.25; % seconds
t = (0:dt:StopTime-dt)'; % seconds
%%Sine wave:
Fc = 60; % hertz
x = cos(2*pi*Fc*t);
% Plot the signal versus time:
figure;
plot(t,x);
xlabel('time (in seconds)');
title('Signal versus Time');
zoom xon;
0 Comments
sevde busra bayrak
on 24 Aug 2020
sampling_rate = 250;
time = 0:1/sampling_rate:2;
freq = 2;
%general formula : Amplitude*sin(2*pi*freq*time)
figure(1),clf
signal = sin(2*pi*time*freq);
plot(time,signal)
xlabel('time')
title('Sine Wave')
1 Comment
Ayesha Noor
on 5 Aug 2021
help me solving this numerical.
Consider x(t) = 1.5sin(πt)[u(t) − u(t − 1)] and h(t) = 1.5[u(t) − u(t − 1.5)] − u(t − 2) + u(t − 2.5). Compute the output y(t) = x(t) ∗ h(t) using MATLAB.
Mehrab Pretum
on 22 Jun 2021
Generate an analog signal using the following equation ,
Signal = 2*sin(2*pi*20*t)+0.4*cos(2*pi*100*t)+0.1*sin(2*pi*500*t)+0.05*randn(size(t));
. Show the signal in time and frequency domain and calculate the capacity using Shannon capacity formula .
• Show the quantize signal considering 6 equally distributed levels and provide image for one cycle of the original signal and quantized signal ( using subplot ) .
1 Comment
Walter Roberson
on 24 Jun 2021
I am not clear on how this will help aaa achieve the sine wave plot they were looking for 9 years ago??
First Last
on 28 Jun 2021
Edited: Walter Roberson
on 5 Aug 2021
t = [0:0.1:2*pi]
a = sin(t);
plot(t,a)
2 Comments
Sourav Roy
on 13 Jan 2022
Edited: Walter Roberson
on 13 Jan 2022
Calculate the following:
- (1/(5^2) + 3/2*pi - 1)^(-3)
- 2*pi - pi^0.5
- 1 + ½ + 1/2^2 + 1/3^3 + 1/2^4
1 Comment
Walter Roberson
on 13 Jan 2022
Please expand on how this helps the poster create a sine wave plot?
Md. Mostafijur Rahman
on 28 Feb 2022
draw the waveforms by using subplot 1.x (t)=u (t) 2. x (n)=u (n+2)
2 Comments
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