Cataclysmic variables from the Calan-Tololo-Survey -- I. Photometric periods

In a search for cataclysmic variables in the Calan-Tololo Survey we have detected 21 systems, 16 of them previously unknown. In this paper we present detailed time-series photometry for those six confirmed cataclysmic variables that show periodic variability in their light curves. Four of them turned out to be eclipsing systems, while the remaining two show a modulation consisting of two humps. All derived periods are below, or, in one case, just at the lower edge of the period gap.