power_confidence_limits

hendrics.power_confidence_limits(preal, n=1, c=0.95)[source] [edit on github]

Confidence limits on power, given a (theoretical) signal power.

This is to be used when we expect a given power (e.g. from the pulsed fraction measured in previous observations) and we want to know the range of values the measured power could take to a given confidence level. Adapted from Vaughan et al. 1994, noting that, after appropriate normalization of the spectral stats, the distribution of powers in the PDS and the Z^2_n searches is always described by a noncentral chi squared distribution.

Parameters
preal: float

The theoretical signal-generated value of power

Other Parameters
n: int

The number of summed powers to obtain the result. It can be multiple harmonics of the PDS, adjacent bins in a PDS summed to collect all the power in a QPO, or the n in Z^2_n

c: float

The confidence level (e.g. 0.95=95%)

Examples

>>> cl = power_confidence_limits(150, c=0.84)
>>> np.allclose(cl, [127, 176], atol=1)
True