Examples of PSD in a sentence
As a result, the measured amplitude of the quasi-periodic surface perturbation with the spatial period of ~8.5 mm (see the PSD spectrum in Fig.
Residual (after subtraction of the specified elliptical shape) surface slope variation (the top trace) and the corresponding PSD distributions evaluated in the spatial and angular frequency domains (the bottom plots) of the reference elliptical mirror.
The OPD RMS is calculated by integrating the respective OPD PSD between 0.1 - 500Hz. We compare these theoretical OPD limits to the OPD residuals measured by the Gravity fringe tracker for the respective calibrator stars.
From these, absolute and relative (peak-continuum) OPD contributions are also calculated, with the peak-continuum OPD contribution calculated as the difference in the integrated PSD over the vibration peak width to the integrated local median over the same domain.
Interestingly, the PSD of the UT telescopes OPD follows more closely the theoretical behaviour of Kolmogorov turbulence for a point aperture, following a near f−8/3 power law up to high frequencies, with no clear signs of the f−17/3 slope theoretically expected from telescope filtering.10 Reasons for this will be discussed in subsequent sections.