jori.hamalainen@xxxxxxxxxxxxxxx wrote: >>>Video being only 1Vp-p in level means only small (20mV or so), levels >>>of mains hum (due to ground loops etc.) are visible in the picture and >>>by keeping the frequencies the same, the hum bars appear stationary or >>>very slowly drifting through the picture and so much less intrusively visible. >> >>Originally yes. To my understanding these problems have been >>long gone (due PSUs) so choice of 50Hz for HDTV makes little >>sence - especially when it comes to digital broadcasting. >>Most likely the decision was based on history and politics. > > > I also agree, but I can be very ignorant on this. HDTV is a 'computer' display. And don't see any banding on my computer monitor which runs with 50Hz mains and 85Hz VGA. Or should I see, and what I should look for? As the poster just above said, these issues are almost irrelevant due to technological advances in various areas. To the decision being based on history and politics, I would also add legacy. It will take some time before stations have enough HD native originated material to fill 100% of their schedules and what about re-runs of pre HD material? Keeping the frame rate the same means standard definition material just needs upscaling, rather than interpolating to a different frame rate as well. Look critically at material that has been NTSC->PAL standards converted to see the compromises the latter involves. Regards, Richard
