Patent ID: 7230615

Claim:
An apparatus for coordinating horizontal and vertical synchronization signals, each of the horizontal and vertical synchronization signals including a series of timing pulses, each of the timing pulses of the horizontal synchronization (HSYNC) signal having a line scan control edge, each of the timing pulses of the vertical synchronization (VSYNC) signal having a field scan control edge, said apparatus comprising: a pulse generating circuit adapted to receive the VSYNC signal and adapted to generate a plurality of critical pulses therefrom, each of the critical pulses defining a critical time period that starts from a logic state transition of the field scan control edge of a respective one of the timing pulses of the VSYNC signal; a determining circuit adapted to receive the HSYNC signal and coupled electrically to said pulse generating circuit for receiving the critical pulses therefrom, said determining circuit generating a trigger signal upon detecting that the line scan control edge of one of the timing pulses of the HSYNC signal appears during the critical time period of one of the timing pulses of the VSYNC signal; and a time delay loop coupled electrically to said pulse generating circuit and said determining circuit, said time delay loop being adapted to introduce a time delay into the VSYNC signal upon receipt of the trigger signal from said determining circuit so as to cause the critical time period of said one of the timing pulses of the VSYNC signal to appear after the line scan control edge of said one of the timing pulses of the HSYNC signal.