Phase Distribution Diagram

In addition to the spectral window and Sock Diagram, SIGSPEC can compute the probability density of phase angles at given frequency as a function of frequency. This is an alternative way to examine the properties of the sampling in the time domain and activated by the keyword phdist:phases in the .ini file. The resulting probability densities are normalised in a way that their mean over all phase angles is $\frac{1}{2\pi}$.

The number of phases to be computed is increased according to the eccentricity of the phase distribution at a given frequency.

In perfect analogy to the Sock Diagram (p.), there are further keywords available to adjust the contents of the output file phdist.dat.

• phdist:fill determines a filling factor for additional frequencies if the changes between the phase distributions for two adjacent frequencies are too high.
• phdist:cyl specifies cylindrical coordinates (height: frequency, azimuth: phase, radial: probability density of phase)
• phdist:cart specifies cartesian coordinates
• phdist:colmodel:lin
• phdist:colmodel:rank
• phdist:colour

Please refer to ``Sock Diagram'' (p.) for a detailed description.

Caution: For frequencies close to zero, tremendous output may be expected! Try to avoid the very low frequency region, if possible.

Figure 14: Phase Distribution Diagram for the sample project output.

Example. The Phase Distribution Diagram in the sample project output is generated according to the following entries in the file output.ini:

phdist:cart
phdist:phases 30
phdist:fill 50
phdist:colmodel:rank
phdist:colour 223 223 223 0
phdist:colour  31  31  31 1

The resulting file output/phdist.dat is displayed in Fig.14.