Figure 1: 
diagram of V 700 Cyg based on the linear ephemeris.
Photoelectric and CCD minima, as well as mean values of several
minimum determinations are shown as filled circles, single visual and
photographic minima are shown as empty circles
A linear least squares solution of the available minima of V 700 Cyg,
listed in Table 1 (available from cdsarc.u-strasbg.fr),
yields the following solution:
Figure 2: 
diagram of AW Vir based on the linear ephemeris.
Photoelectric and CCD minima, as well as mean values of several
minimum determinations are shown as filled circles, single visual and
photographic minima are shown as empty circles
A linear least squares solution of the available minima of AW Vir,
listed in Table 2 (available from cdsarc.u-strasbg.fr), yields the
following solution:
The 
diagram of V 700 Cyg (Fig. 1 (click here)) indicates short-term period
instability, while the diagram of AW Vir (Fig. 2 (click here)) indicates only
marginal period changes - something quite unusual for a W UMa system
that has been under observation for so long.