"Scott Rauscher" wrote in message <firstname.lastname@example.org>... > I've poured through the forums several times and have almost found a good solution. > > I want to fit a sine wave to some under-sampled constant-frequency/phase/amplitude data. I have hundreds of data files so I need to automate it. I have used SineFit in the file exchange, and it works well most of the time, but has a tendency not to converge. I have also tried sinfapm, but the phase it gives never lines up. > > What I'm trying to do is best illustrated in this picture (red is the data, blue is the sine wave I want to find): http://s2.postimage.org/98qvgbnu1/matcode.jpg > > Does anyone have suggestions on where to start for a full-proof way of doing this?
Not enough info.
Do you get a dominant frequency with the dft ? If so, you can estimate A and B from the linear problem