Sine curve for a given period value.

x = data(:,1);
y = data(:,2);
yu = max(y);
yl = min(y);
yr = (yu-yl);                                                   % Range of ‘y’
yz = y-yu+(yr/2);
zx = x(yz(:) .* circshift(yz(:),[1 0]) <= 0);                   % Find zero-crossings
per = 2*mean(diff(zx));                                         % Estimate period
ym = mean(y);                                                   % Estimate offset
fit = @(b,x)  b(1).*(sin(2*pi*x./b(2) + 2*pi/b(3))) + b(4);     % Function to fit
fcn = @(b) sum((fit(b,x) - y).^2);                              % Least-Squares cost function
s = fminsearch(fcn, [yr;  per;  -1;  ym])                       % Minimise Least-Squares
xp = linspace(min(x),max(x));
figure(1)
plot(x,y,'pb',  xp,fit(s,xp), 'r')
grid
fprintf(1, 'Amplitude = %7.3f\nFrequency = %7.3f\nPhase     = %7.3f\nOffset    = %7.3f\n\n', s(1), 1/s(2), 1/s(3), s(4))

estimating these parameters:

Amplitude =   0.503
Frequency =   0.960
Phase     =  -0.803
Offset    =  21.477

and produces this plot:

It was not even necessary to change my original code.

Giru Mishra 2018-5-15

OH okay.. thanks..

Star Strider 2018-5-15

As always, my pleasure.

请先登录，再进行评论。

类别

Signal Processing Signal Processing Toolbox Measurements and Feature Extraction Descriptive Statistics

在 Help Center 和 File Exchange 中查找有关 Descriptive Statistics 的更多信息

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by

Sine curve for a given period value.

0 个评论
显示 -2更早的评论隐藏 -2更早的评论

采纳的回答

13 个评论
显示 11更早的评论隐藏 11更早的评论

更多回答（0 个）

另请参阅

类别

标签

Community Treasure Hunt

Sine curve for a given period value.

0 个评论 显示 -2更早的评论隐藏 -2更早的评论

采纳的回答

13 个评论 显示 11更早的评论隐藏 11更早的评论

更多回答（0 个）

另请参阅

类别

标签

Community Treasure Hunt

0 个评论
显示 -2更早的评论隐藏 -2更早的评论

13 个评论
显示 11更早的评论隐藏 11更早的评论