HORIZONTAL SYNCHRONIZING PULSE SIGNAL GENERATOR

摘要

PURPOSE:To remove variation of a horizontal AFC filter signal by using a horizontal AFC gate signal during phase comparison for a pulse signal generator which is used for sampling a character multiplex signal and television and RGB display. CONSTITUTION:A composite synchronizing signal (j) separated synchronously from a composite video signal inputted to an input terminal 30 is applied to a monostable multivibrating oscillator 32 to generate a horizontal periodic signal (k) from which the influence of the vertical equalized pulse signal in the composite synchronizing signal is removed. This signal (k) is applied to a monostable multivibrating oscillator 33, which generates a horizontal AFC gate signal (l) which has pulse width nearly as wide as the horizontal synchronizing signal. A horizontal AFC circuit 34 gates a horizontal synchronizing integral signal (m) by the gate signal (l) and makes a phase comparison to obtain a horizontal AFC signal (n). Therefore, a stable horizontal synchronizing pulse signal appears at the output of a horizontal oscillation circuit 37 even after a vertical equalized pulse section.