[vsnet-chat 243] Re: PDM troubles

[Taichi Kato <tkato@kusastro.kyoto-u.ac.jp>]

Self-comment:

> The denoted "sigma" is likely to be a measure of the half width of the
> fitted parabola, extrapolated to the zero signal level (P=0), then
> normalized by the degree of freedom (probably assuming the deviation from
> the periodic signal is random and uncorrelated).

   Fourier power should become zero when a shift in trial frequency makes
an effective phase shift of pi (period/2) to the observed data.  So this
would approximate Dr. Mennickent's estimate (vsnet-chat 234) disregarding
the factor arising from the number of observed points.

> A good feeling of the error can be obtained from (order of magnitude)
> P*P/2*T, being P the period and T the range of observing time.

Regards,
Taichi Kato

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