The circuit for detecting field signal exactly by generating window pulse comprises: a controller (100) outputting composite synchronizing signal as control signal; a up/down counter (200) counting the up/down according to the control signal; a first latching section (300) outputting the output of said counter (200) as vertical synchronizing signal; a counter (400) delaying the output of the section (300) for a time, followed by outputting the said output; a second latch section (500) generating the window pulse by latching the output of the first latch section and the counter (400); a field detector (600) outputting the field detecting signal by toggling the composite synchronizing signal combined with the window pulse.
