MultiSine tracks

The MultiSine tracks allow to examine the changes in frequency, amplitude and phase of each signal component in the prewhitening cascade and are an alternative representation of the result files. Instead of a file index that refers to the iteration, the file index of the MultiSine track files m#index#.dat refers to the index of the component in the result files and lists its

1. frequency [inverse time units],
2. amplitude [units of observable],
3. phase [rad]

for each prewhitening step. In other words, a result file displays all the components for an iteration, whereas the MultiSine track file displays all the iterations for a component. Thus the MultiSine track provides a good estimate for the reliability and accuracy of the components found significant.

If the keyword mstracks is provided in the .ini file, MultiSine track files m#index#.dat are generated, where the index #index# starts with 000001, denoting the first significant signal component.

The keyword mstracks expects two integer parameters. The first defines the number of iterations for which entries in the MultiSine track files shall be generated. A negative number causes SIGSPEC to generate entries for all iterations. The second parameter has to be a positive number and defines a step width. If it is set 1, a line in the MultiSine track files is generated for each iteration, if it is set 2, for every second iteration (starting with r000002.dat), and so on.

Example. The sample project output uses the keyword mstracks in the file output.ini, namely

mstracks -1 1

providing MultiSine tracks m000001.dat, m000002.dat,..., for all iterations of the entire prewhitening sequence. The MultiSine track for the primary signal component (file m000001.dat) is displayed in Fig.15.

Figure 15: MultiSine track of the most dominant signal component in the light curve of the sample project output (8.59 cycles per day), according to the output file output/m000001.dat. Left: amplitude vs. frequency. Mid: phase vs. frequency. Right: amplitude vs. phase.