Phill Harvey-Smith wrote: Absolutely.

That statement makes no sense to me at all. PAL is a colour encoding method. SECAM is a totally different colour encoding method. So how SECAM can be essentially PAL with the colour encoded slightly differneetly is beyond me. I think I know what you are thinking. You are assuming that PAL video signals are 625 lines interlaced, 50Hz vertical, And so are SECAM signals. Well, AFAIK, that is not a _requirement_. It's certainly not a requrirement for PAL (there are at least 2 525 line/60Hz PAL standards in the lists I have). If the scan rates are the same you probably would do. All the boradcast colour systems are designed so that they are both-ways compaitble with the related monochrome signal (a monochrome display will corectly display a colour signal as a grey scale, a colour display will likewise display a monochrome signal). There are, I beleive, at least 2 versions of SECAM used too. Philips did various decoder chips for these at one time, but my data books are 20 years old now, and I guess things have moved on... -tony

http://en.wikipedia.org/wiki/File:PAL-NTSC-SECAM.svg On 5/24/10, Andrew Burton <aliensrcooluk at yahoo.co.uk> wrote:

----- Original Message ----- From: "Pete Turnbull" <pete at dunnington.plus.com> To: "General Discussion: On-Topic and Off-Topic Posts" <cctalk at classiccmp.org> Sent: Monday, May 24, 2010 11:14 PM Subject: Re: Pravetz 82 do resolution Really? The *cough* website I looked at listed specific resolutions for each (including NTSC). Perhaps the site had some misleading information? (don't ask for an URL, it's been too long) Regards, Andrew B aliensrcooluk at yahoo.co.uk

----- Original Message ----- From: "Tony Duell" <ard at p850ug1.demon.co.uk> To: <cctalk at classiccmp.org> Sent: Tuesday, May 25, 2010 9:35 PM Subject: Re: Pravetz 82 neither Ok. thanks for the info. Just one more question; why only an odd number of lines? (don't Yeah, and as the web expands theres only going to get more good and bad information online :( Regards, Andrew B aliensrcooluk at yahoo.co.uk

On 27 May 2010 at 19:24, Tony Duell wrote: At least on NTSC, the half-line setup works like this. Scan lines on a TV CRT are not horizontal--they slope slightly down as they are scanned from right to left. So, the second field begins with the beginning of the vertical sweep, but offset from the left of the screen by exactly one-half line. The net result is that the lines on the second field of a frame fall exactly between the lines of the first field. The vertical synchronizing in the US system is quite clever, consisting of varying (depending on odd or even fields) numbers of pre-equalizing pulses (at twice the horizontal frequency) before the vertical sync pulse train and a similarly variable number of post- equalizing pulses following. --Chuck

----- Original Message ----- From: "Tony Duell" <ard at p850ug1.demon.co.uk> To: <cctalk at classiccmp.org> Sent: Thursday, May 27, 2010 7:24 PM Subject: Re: Pravetz 82 of :-) Ahhh, right. Now I see why :) Regards, Andrew B aliensrcooluk at yahoo.co.uk

Pete Turnbull wrote: I can't speak for PAL and SECAM, but the NTSC standard most certainly does specify the number of vertical lines, interlace, and horizontal and vertical sync frequencies. It had to, since the frequencies are different than the sync frequencies used for its predecessor black-and-white system (525/30). The original NTSC standard included both 525/29.94 and 441/30 scan rates, but the latter was dropped at the last meeting of the first NTSC on 8-March-1941. While there exist other unofficial NTSC-related systems such as the so-called "NTSC-J" and "NTSC 4.43", these are NOT part of the NTSC standard. While it is possible to use NTSC-compatible color encoding with different scanning parameters, the result is *not* NTSC. Eric

Chuck Guzis wrote: The deployed 405/25 "System A" was monochrome, and was in service from 1936 through 1985. There were some experimental colour broadcasts using NTSC-like colour encoding with various subcarrier frequencies, most notably 2.6578215 MHz. Reportedly the BBC convinced the government to skip colour on 405/25 and wait for a higher-definition system. There were also tests of 625/25 with NTSC-like colour encoding using a 4.4296875 MHz subcarrier, and while that was never adopted as a broadcast standard, it is sometimes seen as a baseband signal and referred to colloquially as "NTSC-4.43". 625/25 broadcast started in 1963, and PAL colour in 1967. Apparently 405 line service was originally called "high definition", by comparison to Baird's electromechanical system. There's a lot of historical information at: http://www.pembers.freeserve.co.uk/World-TV-Standards/ Eric

While this may have been true in the UK, in the US the major CRT players saw the dollar signs in their eyes, from both RCA's interest in television and the development of inexpensive scopes. -- Will

On 26 May 2010 at 2:26, Randy Dawson wrote: Another life destroyed by "General" David Sarnoff's thievery and underhandedness; Armstrong being the other. I once had the distinction of being in an all-night poker game that was broken up by Mr. Zworykin. (note the spelling). A long story. --Chuck

I wrote: Bj?rn wrote: Interesting. I suppose I should have written "terrestrial broadcast standard". Typically government regulations limit what standards you can use for terrestrial broadcast or direct broadcast from satellite, but anything goes for other satellite transmission. Eric

On 26 May 2010 at 14:47, Alexis wrote: Thank you for the link. A related link: http://www.youtube.com/watch?v=CjK-b4x9ZmQ talks about the Beeb restoring color to black-and-white prints. Very ingenious. It's also the first time I'd seen a clip of "Dad's Army"--up until now, I've only heard the radio version and formed my own mental pictures. It's a bit jarring to have them shattered. --Chuck

On 29 May 2010 at 20:10, Andrew Burton wrote: BBC 7 (internet, DAB, DTV) has been running the series (along with The Goon Show, Hancock's Half-hour, Take it From Me...., etc.) forever, which is where I got acquainted with it. Some of the old BBC comedy shows were pure genius. --Chuck

I believe a few test transmissions occured. The sets were never sold to the general public, but Murphy (IIRC) made a few experimental ones, one of which still exists somwehre. The 405 line standard ('System A') was used for monochrome TV until the early 1980s. When the 625 line standard was introduced in the late 1960s, it was for one station (BBC2) only. Sets were so-called 'dual standard' meaning they had a user control to slect between 405 or 625 lines. Since there were quite a few differences other than just the line freuquency, this control (the 'system swtich' was connected to many parts of the set. Early colour sets were dual standard too, although the colour decoder was disabled on 405 lines. After a time, the 405 line trasnmissions were duplicated on 625 lines too (although the 405 line signals contineud for the benefit of people who had such sets). The frame rate (50 Hz) is the same aas on UK/European 625 line set, of course. I didn't find a correctly set-up 405 line set to be all that bad. A badly set-up one, well.... -tony

What is the offiical name for a composite colour signal (of any scan rates) which uses QAM-encoded colour signals but without the alternate-line pahse switching of PAL? True, but what should it be called? -tony

Randy Dawson wrote: Aside from the fact that RS-170 is a monochrome 525/30 signal (15750 Hz horizontal). Perhaps you meant RS-170A, which is very close to NTSC: color 525/29.97, (15734 Hz horizontal). The actual NTSC standard is contained in 47 CFR 73 Subpart E "Television Broadcast Stations", the most relevant portions of which are 47 CFR 73.682 and selected figures from 47 CFR 73.699. Eric

Ah, here is where we get into muddyness. In the US, we started with NTSC (later called RS-170). NTSC Television or the NTSC System or simply NTSC is a television transmission scheme that includes scan rates, lines, channels, etc. NTSC met again and created what is sometimes referred to as NTSC-II (NTSC with color, RS170A) which includes all of NTSC (modified as needed) as well as a color encoding system. Then we got NTSC-III which is essentially the same thing as NTSC-II but adjusts the color space and some minor details. In Europe, they had System-[letter] to define the line rate, frame rate, channels, etc. They simply added a PAL or SECAM (or no) color encoding scheme but kept the system name. They refer to these systems as PAL-[letter] or SECAM-[letter] so that you have PAL-B instead of "System B with PAL colour encoding" Japan decided to use the NTSC-II (or was it already III at that point?) system but to change the black level to be 0 IRE instead of 7.5 IRE. Someone decided to start referring to this as NTSC-J. Later, someone decided that the US should have a letter too. Let's make it M! Yes! NTSC-M works! (I have no clue whose idea this was, but it makes a mess of the whole NTSC nomenclature) Then we got digital recording. Recordings with NTSC-compatible D1 decks (remember, the ins and outs were still analog and everything had to be in tight tolerance to make this work) were referred to as NTSC-D1, recordings with PAL-compatible 625-line-25-fps-system decks then started getting referred to as "PAL-D1" (ugh... here we go with messy nomenclature again) Then DV came along. Digital in, digital out, mangled formats ("NTSC-DV" and "PAL-DV") that have absolutely no bearing on what color encoding comes out of a deck and the "NTSC-DV" version of which didn't record all visible scan lines... Anyway, what you are looking for doesn't exist. Just call it "NTSC Color" and you'll be better off than these and many, many, many other (don't get me started on DVDs) misnomers. Eric

Not if you can go on for a bit about the burst carrier frequency and how they picked it... Quite a bit of thought went into NTSC, to keep it compatible and add color. The burst 3.758 MHz is chosen to not fit a harmonic of the line rate, frame rate, and that was adjusted too, from 60Hz to 59.xxx, xxx, =975 if I recall but its been a while. Randy _________________________________________________________________ The New Busy think 9 to 5 is a cute idea. Combine multiple calendars with Hotmail. http://www.windowslive.com/campaign/thenewbusy?tile=multicalendar&ocid=…

Right on Eric. With sound at 4.5, you are suggesting they move it up a bit, and make the channel wider? The days of spectrum space, 6 MHz wide for 1 TV broadcast are all now all gone. I'll poke one more TV lore statement, then return the bandwidth to vintage computers. Chanel 2, 54Mhz the lowest of the channels, Houston TX was reported with reception in the UK Salt dome ground plane in the Houston area was cited as a reason, but this channel was well known for DX TV reception. _________________________________________________________________ Hotmail is redefining busy with tools for the New Busy. Get more from your inbox. http://www.windowslive.com/campaign/thenewbusy?ocid=PID28326::T:WLMTAGL:ON:…

Randy Dawson wrote: I guess this why the BBC produced so few westerns. :) Ben.

On Fri, 28 May 2010, tonsofpcs wrote: What percentage of the world uses "Never Twice the Same Color"?

I wrote: Tony Duell wrote: I don't have any opposition to calling a signal "NTSC 4.43", as long as one is aware that this is purely a defacto designation and doesn't correspond to any actual standard (especially NTSC). Eric

Andrew Burton wrote: http://en.wikipedia.org/wiki/File:PAL-NTSC-SECAM.svg Peace... Sridhar

On Sun, 2010-05-23 at 04:40 -0500, Jason T wrote: I would imagine that it would have the same timings as other European Apple II clones, that is an NTSC signal padded to fit the slower PAL timing requirements (or at least that's what I've found with my //c). This would mean it'd be in B&W, unless they also made some sort of converter for it. I'm thinking along the lines of the //c PAL adaptor. SECAM has the same timing as B&W PAL (625 lines interlaced, 15625Hz line freuqnecy, 50Hz field rate) but the colour is encoded with FM instead of QAM and the U and V signals are sent on alternate lines. I doubt they would have gone to the effort of making an Apple II compatible with this scheme, because it really is *awful*. My guess to get it working on an NTSC television would be to adjust your horizontal and vertical sync pots, though it will still be in B&W. Cheers, Alexis.