sine waveform with frequency and samples

Generate 5 seconds of a sinusoidal waveform that has a frequency of 100 Hz and has 15 samples per cycle. Label axes appropiately

ive got here

%%Time specifications:

Fs = ; % samples per second

dt = 1/Fs; % seconds per sample

% Plot the signal versus time:

figure;

plot(t,x);

xlabel('time (in seconds)');

title('Signal versus Time');

zoom xon;

Answer 1

[Mathieu NOE]

%%Time specifications:
f = 100;     % signal frequency
sps = 15;    % samples per signal period
Fs = sps*f;  % samples per second
dt = 1/Fs;   % seconds per sample (time increment)

t = (0:dt:5); % 5 seconds of data (time)
x = sin(2*pi*f*t); % 5 seconds of data (sinus)

% Plot the signal versus time:
figure;
plot(t,x);
xlabel('time (in seconds)');
title('Signal versus Time');
zoom xon;

[Amir Hussain]

class

[Amir Hussain]

that got really messy

Answer 2

[Voss]

Here's how you can do that. This plot is zoomed in, so you can see it

% frequency = 100 Hz = 100 cycles/second
% sampling rate: 15 samples/cycle
% 
% 15 samples/cycle * 100 cycles/second = 1500 samples/second

f = 100; % 100 Hz signal

Fs = f*15; % samples per second
dt = 1/Fs; % seconds per sample

% duration of signal: 5 seconds
% 5 seconds * 1500 samples/second = 7500 samples

T = 5; % 5 second total duration
N = T*Fs; % 5*1500 = 7500 samples

% time goes from 0 to 5 seconds, with N+1 = 1501 samples
% (+1 because linspace includes the end points)
t = linspace(0,T,N+1);

% another way to generate t:
% t = (0:N)*dt; % the same as above

% calculate x at those times:
x = sin(2*pi*f*t);

% Plot the signal versus time:
figure;
% plot(t,x);
plot(t,x,'.-'); % use '.' marker to see (and be able to count) the samples, for checking that it's correct
xlabel('time (in seconds)');
title('Signal versus Time');
zoom xon;
xlim([0 0.1]) % set the xlim to show 0.1 seconds -> should be 10 cycles, again just for verification