CCIR System A (405-line UK) had a 3 MHz video bandwidth and (before 1950) a 5:4 aspect ratio. It also used positive (rather than the more common negative) picture modulation (and AM sound).
TTFN, Mark On 12/8/2011 9:56 AM, Mike Tsinberg wrote:
The 405/25 in 5 MHz will definitely have more horizontal sharpness then 525/30 in 6 MHz If VSB band in NTSC is 1.8 MHz the VSB in 405/25 at 5 MHz would be approximately 1.5 MHz - the baseband bandwidth in 405/25 will be 3.5 MHz In NTSC the baseband bandwidth of 4.2 MHz ideally allows approximately 267 Horizontal pixels. In the 405/25 system the 3.5 MHz baseband bandwidth allows 346 Horizontal pixels. So it will give 30% increase in horizontal resolution. At the same time lower line and frame count gives 23% drop in vertical resolution and 17% drop in temporal resolution. Since vertical resolution was masked by interlaced artifacts and temporal nobody cared at that time the images looked sharper. Best Regards, Mike Tsinberg http://www.keydigital.com -----Original Message----- From: opendtv-bounce@xxxxxxxxxxxxx [mailto:opendtv-bounce@xxxxxxxxxxxxx] On Behalf Of Mark Schubin Sent: Wednesday, December 07, 2011 5:42 PM To: opendtv@xxxxxxxxxxxxx Subject: [opendtv] Re: France bids farewell to SECAM On 12/7/2011 5:00 PM, Olivier Houot wrote:There were discussions on a french forum with a canadian guy that has moved a lot and lived under the three standards at one time or another. He experimented from the Montreal island (circa 2006, i believe). He said that by playing with the settings, he could get a nice picture from Radio-Canada, but when turning to american broadcasts (all by air) from ABC, NBC, CBS, chromatic accuracy was degraded, and it was not possible to compensate with the settings in a completely satisfying way. Also, it was different from channel to channel.Don't ascribe to technology that which can be explained by poor practice. Post-WWII but pre-NTSC-color, a delegation of Americans evaluated British television and found it consistently sharper. That was when the U.S. was 525/30 in 6 MHz channels and the UK was 405/25 in 5 MHz channels. TTFN, Mark ---------------------------------------------------------------------- You can UNSUBSCRIBE from the OpenDTV list in two ways: - Using the UNSUBSCRIBE command in your user configuration settings at FreeLists.org - By sending a message to: opendtv-request@xxxxxxxxxxxxx with the word unsubscribe in the subject line. ---------------------------------------------------------------------- You can UNSUBSCRIBE from the OpenDTV list in two ways: - Using the UNSUBSCRIBE command in your user configuration settings at FreeLists.org - By sending a message to: opendtv-request@xxxxxxxxxxxxx with the word unsubscribe in the subject line.
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