Originally Posted by Ungermann
What about Philips/BTS, who provided cameras for the European 1250-line format? Wasn't it a progressive format?
The late-80s tubed KCH-1000 camera could be modified to do most formats - but that really wasn't a practical production camera, and was only used for trials. The KCH-1000 was certainly also used in the US for 1050/i29.97 research (aka 2 x 525i) which would have been a ~960/i29.97 (aka 960/59.94i) interlaced system. I believe it could also be configured to do progressive (or sequential as it was often then known) as well - but by the time the US went HD, tubed cameras were dead and buried.
The Eureka 1250 standard was interlaced. In modern parlance it would be described as 1152/i25 (or 1125/50i). It had precisely twice the line count (both active and total) of the 50Hz PAL/SECAM 625/50 standards. There was scope in the system planning for receivers using the HD-MAC broadcast standard to use the motion vectors to create an 1152/p50 or 1152/i100 (100Hz refresh rate TVs had begun to be a thing as CRTs got bigger to mitigate 50Hz large area flicker)
Philips created a CCD camera for the Eureka 1250 standard - but that was just for that system - and based around a 1" sensor format. Again this was a prototype really - as so few were made.
The Philips/BTS (Philips = Dutch, BTS = Bosch = German) LDK6000 was a proper 2/3" HD camera and became a workhorse - and was a big seller in the US for two reasons :
1. It could be bought in a triax variant - and operate in sports stadiums that were pre-wired for triax - and didn't require SMPTE fibre runs (as the Sony cameras did). Sony cameras could be used over triax only with off-board converters - known in the UK as 'toasters'... They did not improve HD picture quality...
2. The LDK6000, uniquely, had a CCD sensor design that allowed it to work properly in both 1080i and 720p standards (as well as 480i/p and 576i/p) and at both 50Hz and 59.94Hz (with 23.976/25p added at some point to some variants). This was possible because the CCD sensor wasn't 1080 lines or 720p lines high - it was 4320 lines high believe it or not. That allowed 4 lines to be averaged to create a 1080p image, 6 lines to be averaged to create a 720p image, 8 lines to be averaged to create a 1080i 540line field - with a 4-line offset between each field, 9 lines to be averaged to create a 480p frame (or 18 lines with a 9 line offset to create a 480i 240 line field).
However the LDK6000 wasn't around until a while after US HD production started ISTR - which meant either Sony cameras for 1080i (with a nasty conversation to 720p in the camera CCU and no HD Cam recording for 720p), or Panasonic cameras (which have never had the greatest reputation in system camera terms) with the HD-D5 VTR system (which was 1080i and 720p compatible) which was an SD-D5 VTR with a compression board that took in an HD signal and compressed it into the space taken by an SD signal. (D5 was unusual in that, unlike DigiBeta, it was uncompressed at SD - like D1)
The broadcast format was interlaced, but production was progressive, isn't it?
No - the standard Eureka 1250 system was interlaced all the way through. The only thing that may confuse you about it is that the HD-MAC analogue+digital assistance transmission proposed in the late 80s/early 90s was based around 1:1 288p, 2:1 576i and 4:1 1152i macro blocks based on the speed of motion of blocks of the picture. Unlike the Japanese MUSE analogue compression system (which was 1035 lines high but had major horizontal sub-sampling) the European system had block based motion vectors and switchable 1:1, 2:1 and 4:1 interlace modes on a block-by-block basis to create an SD compatible signal that could be reconstructed to HD in HD receivers.
(Europe had already started - slightly - using D-MAC and D2-MAC which were 625/50i SD component analogue transmission systems, rather than composite PAL/SECAM)
Either way, did the Americans have to purchase from Europe or Japan? What about RCA? Zenith? They stopped manufacturing TV equipment at that time?
By the time the US was going HD there were no US manufacturers of TV cameras or VTRs. (Ampex had effectively stopped making VTRs by then after their DigiBeta rival, DCT, failed catastrophically)
The US had to buy European BTS KCH-1000 cameras to trial their 1050 line HD system in the late 80s, because there were no US camera manufacturers to buy cameras from. RCA and Zenith had long since stopped making broadcast equipment (they'd stopped by the mid-80s).
In Europe we had Philips/BTS (merged) and Thomson (French) - but whilst Thomson had made some pretty lousy tubed cameras for both 1250/50i systems and a 625/50p 'ProScan' format they tried to commercialise, they had not got anything in the HD CCD era that was competitive (they limped on making SD CCD cameras - with the BBC buying a LOT of their cameras)
Grass Valley bought Philips/BTS much later (hence Philips/BTS cameras now have a GrassValley logo - but the cameras are still developed in Europe, mainly at the former-Philips Breda base I think?)
In Japan you had Sony, Ikegami, Panasonic, Hitachi all making 1035i cameras that were then tweaked to 1080i - which was the Japanese standard. Sony and Panasonic had the only HD VTR formats that made sense for general production (HD Cam and HD-D5), and one of those was 1080i only...
Interlace survived for so long because it allowed CRTs to run at high enough refresh rates not to flicker, but without requiring twice the bandwidth to carry the signal.