[old_tv_nut]

another thing, in some formats luminance carrier deviation was increased. Do I understand correctly that this only affects the contrast? Or in other words, it affects dynamic range, considering that more "steps" is available? If this is true, why the increase in carrier deviation is always mentioned together with the increase in luminance resolution? The resolution does not depend on deviation per se, it depends on the overall width of the luminance band, which is expanded if the Y carrier is moved up and the deviation is increased... I see, so it is kind of a secondary effect. But the deviation per se does not improve the resolution?

The FM modulation of the luminance in video tape is called "narrow band" because the FM deviaton is in the same order as the bandwidth of the video baseband. Compare this to FM radio, where the deviation is larger than the baseband audio frequencies.

The overall bandwith of the video tape FM luminance is a combination of the baseband signal bandwidth and the deviation. If the carrier is too low in frequency the combination can suffer distortion.