Bandwidth of video signals from generators with purely digital signal generation

CCIR REC. 624 specifies a signal bandwidth of 5 MHz for standard B,G/PAL. Within this bandwidth, signal rise times or half-amplitude durations of sin 2 pulses of up to 200 ns can be displayed almost undistorted with one restriction, however, namely these signals comprise spectral components outside the 5-MHz band. For instance, the 2T pulse of CCIR 17 has visible pre- and post-undershoots, but they are not significant enough to impair measurement results. In signals with a rise time of 100 ns (eg 250-kHz, 15-kHz squarewave signals) components outside the nominal VF bandwidth are considerably greater and cause a transient response with pre- and post-ringing of approx. 3%.