Terminology

Within XRONOS the user has full control of the binning to be used in the analysis, the way of subdividing a time series and/or grouping the results of the analysis. To this aim four basic entities are used in most XRONOS applications:

• BINS : these are the time bins of the time series which is/are being analysed. Note that there can be more than one bin durations, (e.g. two consecutive time series, one with 0.5 s bins and the other with 2 s bins). In the examples in chapter 3 (walk_through) the input files contain 743 bins of 1 s.

• NEWBINS : these correspond to the time resolution with which the analysis is carried out. One of the examples in section 3.1.2 (walk question psd) shows how to calculate a power spectrum using a 3 s resolution, i.e. newbins of 3 s. Note that: (i) newbins cannot be shorter than the longest bin duration of the time series which is/are being analysed; (ii) in many XRONOS applications (e.g. psd, pss, acf, ccf) the newbin duration is forced to be an integer multiple of the longest bin duration.

• INTERVALS : an interval is defined by the number of newbins over which the analysis is carried out. One of the examples in section 3.1.2 (walk question psd) shows how to calculate power spectra for intervals of 64 newbins of 3 s, corresponding to 32 independent Fourier frequencies. Note that in applications using FFT algorithms (e.g. psd, acf, ccf) the number of newbins in an interval must be a power of 2.

• FRAMES : a frame consists of the average of the results of the analysis of one or more contiguous intervals. Each XRONOS QDP file and, therefore, each plot produced by XRONOS corresponds to a frame. The examples in section 3.1.2 (walk question psd) show how to average the power spectra from 1, 2 or 4 intervals (each of 64 newbins of 3 s) in a frame. Note that in certain applications (e.g. lc1, lc2 and lc3), a frame consists always of one interval.