LINE DEFLECTION SYSTEM AND HORIZONTAL CENTERING CIRCUIT FOR VIDEOSIGNALS FROM ALTERNATIVE SOURCES Russian patent published in 1998 - IPC

FIELD: television, videosystems. SUBSTANCE: invention is aimed for adjustment and maintenance of phase relation between videosignal (in II) and signal synchronizing scanning (in 67) ensured in line deflection system 40 to guarantee proper centering along horizontal line. First phase closed loop generates first time signal (in 17) on first frequency in step with line synchronizing component in video signal. Counting circuit installed in advance (in 56) functions in step with first time signal for division of clock signal (in 61) on second frequency. Second phase closed loop 62 generates signal synchronizing scanning (in 67) from second time signal. Microprocessor 74 may send various number into register (in 56). Output of register is connected to counting circuit installed in advance. Various numbers from microprocessor 74 change relative phase between first and second time signals by growing steps. Microprocessor 74 controls switch of selection of videosource to extract one of alternative videosources in the capacity of output of video and synchronizing signals and to regulate relative phase between line synchronizing component of selected videosource and synchronous time signal with the aid of coefficient corresponding to selected videosource. Hand-controlled circuit 72 may be placed in route of feedback of second phase closed loop 62 to regulate relative phase between second time signal (in 61) and signal synchronizing scanning ( in 67) within range corresponding to growing step. EFFECT: improved capability for adjustment and maintenance of phase relation. 28 cl, 8 dwg