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I was wondering what is the practical difference between Lagrange Interpolation using Farrow Structure and Sinc Interpolation? Both require pre-computation of time offset coefficients using a lookup table.

Is the length of filter required for a certain degree of accuracy less for one over the other? How do they compare?

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    $\begingroup$ it turns out that, since both Lagrange and windowed sinc have the interpolated function go directly through the original points, you can actually come up with an effective impulse response for Lagrange that looks like a sinc. you can divide that Lagrange impulse response by a sinc, deal with the 0/0 singularities and come up with an effective window. Lagrange is an example of windowed sinc. $\endgroup$ – robert bristow-johnson Dec 7 '19 at 21:42
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    $\begingroup$ @PeterK. Kootsookos and Williams (1995) have proved that the Lagrange interpolation coefficients can also be obtained by windowing the shifted and sampled sinc function with a scaled binomial window... May be you have samething to say... $\endgroup$ – Fat32 Dec 7 '19 at 22:13
  • $\begingroup$ I understand that in the limit the Lagrange interpolation approaches ideal sinc but that doesn't address the question of windowed sinc vs windowed lagrange. $\endgroup$ – FourierFlux Dec 8 '19 at 1:09

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