Title: Correlation plots of the Siberian radioheliograph,
Abstract: The Siberian Solar Radio Telescope is now being upgraded. The upgrading is
aimed at providing the aperture synthesis imaging in the 4-8 GHz frequency
range, instead of the single-frequency direct imaging due to the Earth
rotation. The first phase of the upgrading is a 48-antenna array - the Siberian
Radioheliograph. One type of radioheliograph data represents correlation plots.
In evaluating the covariance of two-level signals, these plots are sums of
complex correlations, obtained for different antenna pairs. Bearing in mind
that correlation of signals from an antenna pair is related to a spatial
frequency, we can say that each value of the plot is an integral over a spatial
spectrum. Limits of the integration are defined by the task. Only high spatial
frequencies are integrated to obtain dynamics of compact sources. The whole
spectrum is integrated to reach maximum sensitivity. We show that the
covariance of two-level variables up to Van Vleck correction is a correlation
coefficient of these variables.