
426
Fig. 23.9 Nine-line interlaced 'raster'. The dotted lines are flybacks, which normally
are invisible
confusingly, because it has nothing to do with electric or magnetic
fields).
A scanning diagram showing all 625 lines would be difficult to
follow, so Fig. 23.9 shows a raster (as it is called) of only 9 lines. The
principle is the same, however. Beginning at A, the line time base
scans line No. 1, at the end of which the flyback (shown dotted)
brings the spot of light back to the left-hand edge. But not to A, for
the field time base has meanwhile moved it downward two spaces to
B.
In the same way all the odd lines are scanned, until No