create Continuous sine wave with fixed frequency

Hi,

i want to create a contiuous sine wave, with a frequency of 0.2Hz.

I want the wave to start when the x-axis is at 200. Now i wrote some code but i want to expand the time of an oscillation from 5s. to something else. how do i do that?

speed = 27.8;
straighttime= 5560/speed;

step=2;

time = 0:step:1200; 
waypointsdata=0.2*sin(2*pi*0.2*time);  
transpose(time);                
transpose(waypointsdata);
waypointmarkers = [time;waypointsdata]'; 

if straighttime >0
strike = round(ceil(straighttime)/step);
waypointmarkers(1:strike,2)=0;
end 
waypoints(:,[1,2]) = waypointmarkers;
waypoints(:,3)=zeros;
plot(time,waypoints(:,2)) , grid on

Answer 1

[Dana]

freq = 0.2; % freqeuency of sine wave (pick whatever you want)
T0 = 200;   % period sine wave starts
T1 = 240;   % period sine wave stops
smprt = 20; % Sampling rate (plotting points per period of the sine wave).
        % If this is too low, the plot won't look right.

t = linspace(T0,T1,ceil((T1-T0)*freq*smprt));   % sampling times
x = sin(2*pi*freq*t);   % sine wave value

% pad t and x with an initial zero to start plot at (0,0); we'll cut the
% plot off later
t = [0,t];
x = [0,x];

figure(1)
clf
plot(t,x)
xlim([175,242]) % set the x-axis limits (roughly what you had in your fig.)