PURPOSE: To enable to output the signal synchronizing with a vertical synchronizing signal by means of period leading-in from a pulse generator by applying pulse comparison with vertical synchronizing output to the output of the pulse signal generator and providing the output to the reset terminal of requency divider.

CONSTITUTION: The clock signals with N-times the frequency of holizontal synchronizing signal are repeated and the frequency is entered input terminal 1 of frequency divider 8 by which the dividing output which is equal to the vertical synchronizing signal can be obtained, so that it is synchronized with the reset signal of divider 8. The input terminal of pulse signal generator whose output is the signal with optional P-times the pulse width of the reset signal is connected to the output side of frequency divider 8. The output of generator 7 is sent to terminal 3 as a vertical scanning output and phase comparision 8 with the vertical synchronizing output is applied to it; the compared output is connected to the reset terminal of divider 8. Thus, pulse signal generator 8 can output the signal which synchronizes with the vertical synchronizing signal by means of period leading-in