View Single Post
  #6  
Old 01-11-2017, 02:30 PM
ppppenguin's Avatar
ppppenguin ppppenguin is offline
VideoKarma Member
 
Join Date: Oct 2009
Location: London, UK
Posts: 445
Only a few of the 2" cart machines found their way to the UK for use by the ITV companies. Their main use was for playing out commercials so the BBC had no use for them.

There's an interesting snippet at the end of that video showing the facilities at ITN, London. At 8:37 you can see the huge analogue PAL<>NTSC converter. This was built by Pye to a BBC design. The BBC prototype, the world's first all electronic field store converter, was available just in time for the 1968 Mexico Olympics. THis was the first that had the possibility of live worldwide coverage.

The converter occupied 7 full height 19" rack cabinets. The storage medium was quartz delay lines, each giving 3.2ms delay. Like a monstrous version of the commonplace PAL delay lines. They were multifaceted quartz polygons, the signal being transmitted by a transducer on one face and bounced around many times until it reached the receiving transducer. They were in temprature controlled cabinets to keep the delay constant.

The line rate conversion was handled by a pair (one each for Y and C) of linestores. These were based on the earlier BBC analogue 625 to 405 converter. In very crude terms these were a pair of electronic multiway switches connecting to a bank of 576 capacitors, one for each pixel (except the term pixel hadn't been invented at the time).
__________________
www.borinsky.co.uk Jeffrey Borinsky www.becg.tv
Reply With Quote