MEASUREMENT DEVICE FOR CONVERGENCE

摘要

PURPOSE:To decrease the time of measurement and to improve the measurement accuracy by measuring the convergence (color blurring) of optional plural positions on a color TV screen within the minimum number of fields. CONSTITUTION:The convergence measurement order is shifted to positions of vertical patterns VP1-VP5 in response to the traveling order of a scan line S of an ITV camera, and the measurement positions are shifted as P1 P6 P11 P21... P25. The position (number) of the line S is shifted successively at and after the head position to measure the time tRm (tGm, tBm) between a horizontal synchronizing signal and the vertical pattern. Then these 25 measurement positions P1-P25 are measured in a single field. The measurement time of those 25 positions is defined as 1/60secX1 16.7msec. This means a big reduction of the measurement time. Then the measurement is carried out at the position (x) in order of P11 P16 P21 P1 together with a shift given to the number of the line S. Hereafter the measurement is performed in the same way at all positions P1- P25 with five lines S shifted successively. In such a way the measurement accuracy is improved.