15-04-2016, 09:55 AM
(This post was last modified: 15-04-2016, 09:57 AM by Geordie McBoyne.)
Why did South Africa chose System I? I'd say not only for political reasons but also for technical reasons as well. One of the best authorities on world TV systems is vintage-radio forum contributor "Synchrodyne". Link to a topic on the UKVVVR: http://www.vintage-radio.net/forum/showt...hp?t=83653
We now know that the origins of the 625 line system go back to the end of WW2 and results of the development of the system by Russian engineers. In essence the Russians modified the American 525/60 system to work in the 50Hz mains supply environment. A 50Hz picture field repetition rate instead of 60Hz means that you can fit in 312.5 lines per field. better vertical definition but perhaps a little more flicker.
The Russians opted for 6.5Mz vision sound spacing in order to get the best possible horizontal picture definition, the objective was to emulate the quality of 16mm film.
As for system I, it is reckoned to be the best compromise for a 625 line TV system operating in an 8Mhz channel. A lot to do with the width of the vestigial sideband which I believe is 1.25Mhz for system I. The Russian and Continental systems compress the VSB to a lesser figure. Max system I vision bandwidth of 5.5Mhz. 6Mhz system D,K.
Did SA use Band 1 or Band 3 for their TV system or did they opt for UHF right from the start?
Geordie McBoyne.
We now know that the origins of the 625 line system go back to the end of WW2 and results of the development of the system by Russian engineers. In essence the Russians modified the American 525/60 system to work in the 50Hz mains supply environment. A 50Hz picture field repetition rate instead of 60Hz means that you can fit in 312.5 lines per field. better vertical definition but perhaps a little more flicker.
The Russians opted for 6.5Mz vision sound spacing in order to get the best possible horizontal picture definition, the objective was to emulate the quality of 16mm film.
As for system I, it is reckoned to be the best compromise for a 625 line TV system operating in an 8Mhz channel. A lot to do with the width of the vestigial sideband which I believe is 1.25Mhz for system I. The Russian and Continental systems compress the VSB to a lesser figure. Max system I vision bandwidth of 5.5Mhz. 6Mhz system D,K.
Did SA use Band 1 or Band 3 for their TV system or did they opt for UHF right from the start?
Geordie McBoyne.
