Thread Subject:

converting displacement to velocity

I have a vector x which represents displacement over time. If I use the code diff(x), does it brings me the first derivative of the displacement i.e. velocity??. Else, Is there any other way to find velocity from the displacement??

On 5/6/2011 12:16 PM, mahesh bvm wrote:
> I have a vector x which represents displacement over time. If I use the
> code diff(x), does it brings me the first derivative of the displacement
> i.e. velocity??. Else, Is there any other way to find velocity from the
> displacement??

It's an approximation of the first derivative, sure...for it to be
displacement you'll have to account for the sampling frequency, etc., ...

As another poster (was it you?) just asked a day or so ago, there's
another thread that discusses some of the pitfalls worth looking at (the
obvious of any DC or low frequency component is one such).

One can also do things like fit (splines are useful here on occasion)
and differentiate them or similar "tricks"...

--