[mathcad] Re: DSP method

Author: Chris Whitford Posted: Thu, 12 Jan 2006 09:14:00 +0000

You could take the cross-correlation and find the peak. To do this, Fourier
transform both waveforms, multiply one by the complex conjugate of the
other, then inverse transform. If the signals are periodic there will be
multiple peaks; use the one closest to zero.

Chris

At 17:26 11/01/2006 +0000, you wrote:
>I have 2 digitised signals (A2D sampled) which are very similar in shape
>but differ by a fixed time difference, can anyone suggest methods which
>will allow me to calculate what the time difference is?
> I have the feeling that if i can somehow use all the data I should get a
> much more accurate value than say just comparing a zero crossing of the 2
> traces which I think will be far more susceptable to noise in the signal.

+ Chris Whitford
+ Research Fellow, University of Leicester, Space Research Centre,
+ Physics and Astronomy Department, University Road, LEICESTER LE1 7RH, UK
+ Tel: +44 (0)116 252 3496, Fax: +44 (0)116 252 2464
+ email: "chw" http://www.star.le.ac.uk/

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