567-line television system

{{Short description|Early experimental television system}}

The 567-line television system was an experimental late 1940s{{Cite news |date=1948 |title=Philips bringt ein neues Fernsehsystem |work=Funktechnik |issue=2 |location=Austria |url=http://www.scheida.at/scheida/TV_SEITE/philips_48_I.jpg}}{{Cite news |date=1948 |title=Philips bringt ein neues Fernsehsystem |work=Funktechnik |issue=2 |location=Austria |url=http://www.scheida.at/scheida/TV_SEITE/philips_48_II.jpg}}{{Cite book |url=https://link.springer.com/book/10.1007/978-3-642-92591-7 |title=Fernsehen |date=1953 |language=en |doi=10.1007/978-3-642-92591-7 |isbn=978-3-642-92592-4 |s2cid=244293816 |editor-last1=Leithäuser |editor-last2=Winckel |editor-first1=G. |editor-first2=F. }} proposal by Philips of the Netherlands for a European television system, with some test transmissions being made from Eindhoven.

The first mention of the system appeared in an article from 1938, published in the Philips' technical bulletin, on a transportable demonstration TV station, running an at 50 fields (25 frames) per second,{{cite web |title=Philips Netherland 567 line TV Standard |url=http://www.radiomuseum.org/forum/philips_netherland_567_line_tv_standard.html |access-date=2011-06-20 |publisher=Radiomuseum.org |language=de}} but no more details were provided.{{cite journal |last1=J. van der Mark |title=A transportable television installation |journal=Philips Technical Review |date=January 1938 |volume=3 |issue=1 |page=2 |url=https://worldradiohistory.com/Archive-Company-Publications/Philips-Technical-Review/30s/Philips-Technical-Review-1937.pdf |quote=The installation is suitable for the broadcasting of 25 pictures per second, with 405 or 567 lines per complete picture, while interlaced scanning is employed. (If 567 lines are used, a frequency spectrum must be dealt with which extends from about 50 cycles per second to about 5 × 10⁶ cycles per second, for 405 lines the necessary frequency spectrum extends only to 2.5·10⁶ cycles per second.}} Most of the technology was to be borrowed from the American 525-lines system, the difference being the reduction of horizontal scan frequency from 15,750 to 14,175 Hz.{{cite web |last=Scheida |first=W. |date=2006 |title=Fernsehen in Holland - in den Niederlanden |url=http://www.scheida.at/scheida/Televisionen_Netherlands.htm |access-date=2011-06-20 |website=Virtuelles Museum des Fernsehens |publisher=}} This would have meant that the American sound carrier frequency of 4.5 MHz above the picture carrier would have also been the standard for Europe, and hence a lot more common worldwide.

By 1950 some 567-line television sets were built and distributed to Philips employees for home testing.{{Cite web |title=Philips TX594U - Television receiver for experimental broadcast, VHF channel 4 only, 567 lines. |url=https://www.radiomuseum.org/r/philips_tx594utx_594.html |website=Radiomuseum}}

The 567-line system was proposed for international use but never adopted. Russian engineers had already shown how 525-lines could be easily adapted to a higher resolution by breaking with American 6 MHz channel bandwidth restrictions and moving the sound carrier up from 4.5 to 6.5 MHz, along with 625-line scanning. This 625-line system was eventually approved as CCIR System D.