"Scanning for one picture with the blanking data at the rear half of each of the first field period and the second field period is completed in half of one frame period of the original image: 16.7 ms, i.e. about 8.4 ms in the same manner as that of the scanning for one picture with the video data irrespective of setting for the combination of gate lines for each two lines in the second field period" . . . .