LabVIEW
Simple Interpolation
Here's a quick example of a simple interpolation, which just takes the value of one index and averages it with the next one up (although, this'll give 99 values total rather than 100).
Hope this helps!
Message Edited by corys on 06-05-2008 09:09 AM
Yeah, I thought that would be a bit too simple, but it was worth a shot 
To my recollection, there are many ways to go about doing a spline interpolation (mine would be akin to a linear spline interpolation, no?), but maybe my memory is not doing me any favors. Maybe if you could expand on that a bit?
Are you trying to obtain 100 values rather than 50 while acquiring your signal, or taking 50 obtained values and expanding them to 100? If expanding from 50 obtained values, what kind of signal are you expecting (or namely, what type of interpolation would be more appropriate?)
Tryin' to get a better idea of what you're needing, to try and help.
Those VIs are pretty simple to use and very powerful. The Interpolate 1D VI can do many different types of interpolation, including linear and spline. It should definitely fit your needs.
There are two ways to indicate to this VI how you want to resample your data. You can input an array of X Values that correspond with your Y Values array, and then input a new array of desired X Values for the interpolated Y array. For instance, suppose I have X = [0, 1, 2] and Y = [100, 200, 300]. I can resample Y with interpolation to be about twice as long by specifing an xi array of [0, 0.5, 1, 1.5, 2]. The resulting Y array has interpolated values for all 5 desired X points.
Alternatively, if you simply want to insert samples between the existing Y values at evenly spaced intervals, you can use the N Times input to specify how many samples to insert between each Y Value. This assumes, of course, that all Y Values are evenly spaced over time. If this is the case, to roughly double the size of your array with spline interpolation, all you need to do is the following:
Message Edited by Jarrod S. on 06-05-2008 11:56 AM
There are two ways to indicate to this VI how you want to resample your data. You can input an array of X Values that correspond with your Y Values array, and then input a new array of desired X Values for the interpolated Y array. For instance, suppose I have X = [0, 1, 2] and Y = [100, 200, 300]. I can resample Y with interpolation to be about twice as long by specifing an xi array of [0, 0.5, 1, 1.5, 2]. The resulting Y array has interpolated values for all 5 desired X points.
Alternatively, if you simply want to insert samples between the existing Y values at evenly spaced intervals, you can use the N Times input to specify how many samples to insert between each Y Value. This assumes, of course, that all Y Values are evenly spaced over time. If this is the case, to roughly double the size of your array with spline interpolation, all you need to do is the following:
Message Edited by Jarrod S. on 06-05-2008 11:56 AM
