TIME BASE COLLECTOR CIRCUIT

PROBLEM TO BE SOLVED: To provide a time base collector circuit capable of interrupting the disturbance of an output video signal caused by the disturbance of a video signal inputted up to the completion of PLL repull-in of a horizontal synchronizing PLL circuit due to the vertical pull-out of an input video signal generated by the switching of channels or the switching of plural video sources. SOLUTION: A synchronism separator circuit 13 extracts a vertical synchronizing signal VSYNC from an analog input video signal inputted from an input terminal 1, a vertical synchronizing pulse width checking circuit 15 and a vertical synchronizing interval checking circuit 16 respectively check the pulse width and pulse interval of the extracted signal, and at the time of detecting abnormality, the writing of a field corresponding to the abnormality in a field memory storing video signals for two fields is stopped. Since a video signal is extracted only from the other normal field, the video signal having no disturbance can be always outputted from a video output terminal 11.