Talk:Analog television

Could someone add the maximum number of Analog channels?

I got into a discussion and some persisted that Ch 7# where the highest analog channels. I thought this was b/c that is all they have ever encountered. Since my TV goes up to 120 or beyond for analog stations. So what are the possible channels for analog TV in the US and elsewhere. Both Broadcast / and Cable etc. EDIT I guess this site says Broadcast is 2 - 83. http://electronics.howstuffworks.com/dtv3.htm How about cable though can it go all the way to 12#? TY

Hello, as a Radio Amatuer with my own station, and speaking as an electronics engineer in T.V. and Radio since 1963, I can only provide the information for the historical U.K. channels. In the 1950s 405 line T.V. transmission were made on V.H.F Band 1, it was 5 channels only, (all B.B.C.), then in the 60s Band 3 was used for independant commercial stations (ITV) - channels 6 -13. Band 2 was designated for use by F.M. Radio stations. In the mid 60s, a new system of 625 line colour transmissions was introduced on the U.H.F band. This band had channel numbers designated for 21 - 68 (for use by all companies). Digital multiplexed transmission technology allows a greater number of channels to occupy the same analogue channel space. So, I guess as time goes on and different multiplexed modes evolve, more and more "channels" will appear in the same frequency allocation. The total number of broadcast "channels" (frequency allocation) is set by international agreement. This is done to minimise the effect of co-channel interference between geographical areas (and countries). see OFCOM in the U.K. for band plan information and allocated frequencies (channels) for broadcast stations. I have my own band plan of allocated frequencies (channels) I can broadcast on using different modes (T.V., CW etc). Hope this helps.Francis E Williams (talk) 17:43, 23 November 2010 (UTC)

It used to be that US channels went 2 to 83, for 82 channels. VHF, 2 to 13, is 54MHz to 216MHz, with some holes, such as for FM, and other radio systems. Then UHF from 470MHz to 890MHz for 70 channels 6MHz wide. Note the big space between 216MHz and 470MHz where no TV channels exist. Cable can use those frequencies, as long as they don't interfere with other uses. Somewhere in Wikipedia there should be a table of assignments for analog cable TV channels. In any case (470MHz-216MHz)/6MHz allows for 42 more channels, so up to about 125 for the usual analog cable system. Gah4 (talk) 15:35, 25 March 2020 (UTC)

Why???

This doesn't seem fair!!! What about all the people who don't have the equipment to receive digital broadcasts??? What are we supposed to tell them??? Sounds a little "right-wing", don't you think??? --WIKISCRIPPS 07 SUN SEP 24 2006 2:43 PM EDT

Some have said the real reason for getting rid of analog TV is for more bandwidth for cell phone. if that is the case, we would be better served by not letting every idiot and 10-year old kid off the street from having one. 1 phone per household is fine, but 1 person= 1 phone is assinine. -WK- 139.78.96.57 (talk) 00:24, 28 December 2007 (UTC)

Here's the deal: Those who still have analog TVs without tuners capable of getting ATSC signals, will likely be given a set-top box at discount. That, though will be a minimal problem, as the law already mandates that any television over 27 inches (around that at least) must have an ATSC compatible tuner.

I think smaller TVs will be required to have this compatibility soon enough. At the rate most people go through televisions, ATSC, Digital TV and HDTV will come on the scene with much fewer problems than you think. Serkali 06:24, 7 December 2006 (UTC)

Now what if can't afford it??? Why do we come sooner than other countries and why is this even necessary??? Not to be disrespectful, but analog signal removal sounds too "right-wing" and too "conservative" for me to handle!!! --WIKISCRIPPS 07 THU DEC 07 2006 1:38 PM EST

I don't understand how that fits with the popular conception of "right wing" or "conservative"- aren't the conservatives the guys clinging to their ancient dinosaur-powered cars while the liberals want everyone to be forced to buy electric or fuel cell cars? (an exaggeration, but only just) -216.138.38.86 15:44, 26 January 2007 (UTC)

Well, now hear this... Not everyone can afford such technology so what are we supposed to do??? It's a stupid idea, they should just the leave the analog signals alone!!! At least with an analog TV set you can still use a VCR!!! The new HDTV sets are too expensive!!! If was in Washington, I would see to it that any station that dares to remove its analog signal, I would its license revoked for turning on its viewers!!! The concept has "arrogance" and "controversy" written all over it!!! --WIKISCRIPPS 07 MON FEB 19 2007 8:07 PM EST

Ha ha! the thought of how to watch DTV with my Sony Watchman pocket TV, I wonder where I'll be able plug in the set top box? MarkRBarker 11:59, 13 January 2007 (UTC) markrbarker

I've got a 1960's Duel-standard Sony portable (For any americans reading this, in 1964 when the BBC started BBC 2 they had to use a 625-line (PAL) system as opposed to 405 line standard transmissions, duel-standard means that they can pick up both signals) that can be plugged into a car cigarette lighter (Sony obviously didn't realise that in-car Television sets were banned in the 1950's) and will be useless by 2009 (that's when the Granada television region gets switched off) I am so annoyed by the British governments decision that I've started a petition to stop this lunacy (I do wish that they'd keep Tony Blair locked in his padded cell at the full moon!)

I sympathise with people who wont be able to use their pocket TVs any more, but to be honest you are in the extreme minority, and it is far more beneficial to free up the bandwidth that is currently occupied by the redundant analogue signal. As for those of you complaining that digital TV technology is too expensive, please do your research before you decide to moan about every little thing that the government does that affects you; I bought my set-top box for £20 - that's right £20! That's $10 (oops! $40, my bad maths) for those in the US. If anyone now claims they still can't afford the conversion to digital, maybe you should stop watching so much TV and go out and earn that extra £20 that you need. I can't beleive the things some people will moan about. Hpesoj00 19:50, 8 July 2007 (UTC)

I'm not speaking for myself. I have DirecTV, so according to Tom Weedon, I'm set. No, I'm speaking for the millions of retired senior citizens who are on a very fixed income who don't have generous relatives (such as a nephew) who'd be willing to buy a converter box for them because after paying bills, they wouldn't have enough for the little niceties.

Anyway, what's all this expense for, really? A prettier picture? That money could go for more important things such as education (public schools), social security, healthcare, etc. -- John R. Sellers, US citizen.

Whilst I feel that this is probably diverting into a debate rather than discussing the article, I do think this reveals one of the fundamental flaws with this article. It bases its observations, which IMHO verge at the very least on Original research, on how a particular country implements its digital TV system. For example, GeorgeFormby1 misses a great deal of context about the British situation which is relevant here, such as:

• Digital TV in the UK is strongly influenced by Freeview (and its soon to be launched sister Freesat), which are subscription free digital TV systems that the BBC (the UK's very dominant (compared to the US) public broadcaster is the key stakeholder in. As pointed out by Hpesoj00, Freeview boxes now retail at around £20 (actually around $40). Although, it may seem a lot to pensioners in the US it is small compared to the annual, compulsory, Television licence fee of around £130per year ($260).
• Europe has traditionally had a much stronger regulatory framework with regards to broadcasting. Where as, (if i understand correctly) in the US, cities are well served and rural areas often poorly served (in some cases having to pay to have affiliates and stations from other markets relayed to them so they can actually have a TV service at all), most of the traditional "analogue" channels in the UK and Europe(in the UK: BBC1, BBC2, ITV, C4 and to a slighlty lesser extent Five, whose availability is constrained by the amount of bandwidth that was left in Europe by the time it started in 1997) are obliged as part of their licence to be available universally i.e. In the UK, >98% coverage of the UK landmass. This means that European airwaves tend to be very crowded and together with the stronger licensing rules means that there are relatively few analogue channels (UK homes get 4 or 5 channels, and 6 in a *small* number of cities, where (usually) community groups are given a *low* power licence.)
• The above therefore identifies the reason why a lot of European countries had an appetite for more channels when digital TV came along. The restricted space available, particularly terrestrially, has meant that channels tend to be crammed into the available space, and indeed some digital channels have a very poor picture quality compared to a good analogue signal. But this only tells half the story, implementations vary even in one country, for example in the UK compare the bit-rates of BBC1 digital are at about ~6Mbps compared to those on Mux A which run at <2Mbps (e.g. Five Life et al). Thus, the resultant picture quality is purely down to the implementation, that various multiplex owners have chosen to take and is not indicative of digital TV in general. Indeed, as I understand in the US, where homes generally have a much greater number of channels but are "afflicted" with the inferior NTSC system. The application of digital TV has generally been to deliver HDTV as opposed to large quantities of new channels...

... and indeed that brings the question of what it is all for! In the UK and Europe large swathes of digital space are reserved for the public broadcasters (without getting into a debate over whether all this space is used for programming that is truely public service), post digital switch-over this will allow every home in the UK to access free-to-air and terrestrially (the way most people receive TV in the UK) channels such as BBC Parliament (coverage of parliament), BBC News 24 (likely to be the UK's only free-to-air rolling news channel before long), BBC Four ("high brow" arts and culture), Teachers TV (a channel for Teachers), etc, etc,. 18:32, 12 July 2007 (UTC)

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This is entertaining. Personally, I am looking forward to seeing antenna televisions hooked up to DTV in the good old USA. I am very excited to see the images of old-school televisions coming face-to-face with a sleek black converter box! I can't imagine a little pocket televison or a "rabbit-ear" vintage black-and-white TV recieving the Weather Channel, or C-SPAN, or the History Channel! What a fantastic world this is! I'm just glad the government acknowledges the Analog generation, giving them converter boxes dirt cheap (in comparison).

Also, those boxes are fifty dollars ($50) per set at Radio Shacks here in the Southern United States, and the 2009 Transition site is givng away coupons to further reduce that. It shouldn't be too hard to get your hands on one!

To quote the country singer, George Jones, this is gong to be like "Mayberry meets Star Trek", which was from his song "High-Tech Redneck". Quite a nice tune.

--TurtleShroom! :) ^†Jesus Loves You and Died for you!^† 15:52, 6 February 2009 (UTC)

POV

Does this article seem biased towards analog TV to anyone else? -216.138.38.86 15:45, 26 January 2007 (UTC)

The point is that this artcile is about analogue television. The same situation can, for example, be observed with MP3, while Ogg Vorbis is the better format (because it's free). -Mardus 06:12, 10 March 2007 (UTC)

Mardus, of course it is OK for an article to talk mostly about the subject and briefly cover the related topics. However, the section "Comparison of analog and digital television" should really be called "Advantages of analog over digital television". If a page is going to compare the subject with related subjects, it should compare them in a fair and balanced way. The reason everywhere is changing to digital is that it is superior to analog overall. The only advantage of digital listed by the editor of this section is the fact that it can deal with a low power signal without breaking up. This section is definitely a one sided view. Hpesoj00 13:37, 15 March 2007 (UTC)

I do concur with this. One disadvantage of digital television is that older TV equipment that still works cannot be used to receive the signal. But there should therefore be more advantages listed, because I don't feel that just one advantage is enough reason to switch. -Mardus 17:35, 16 March 2007 (UTC)

It is very difficult to compare analogue and digital television picture 'dynamics' quality by viewing as current day broadcasts, the best that can be done at present is to find VHS recordings of TV programs made when the analog signal was maintained, such as in the early 90's. If you don't beleive me, try it and see for yourself- look for the picture movement, one looks more like real-life, the other looks like moving computer graphics. Analogue RF signals nowdays are not maintained, they are allowed to degrade, making it difficult to see the picture without snow and of course is still subject to the effects of digital compression which may be used now to save bandwidth in the transport feed. The difference A and D TV can be equated to the difference between an original audio CD and an 'all-digitally-mastered' MP3 download of the same 70's or early 80's track, the latter of course sounds as though it is heard through short-wave radio, listen for the varying timbre of fuzz-guitar which MP3 cannot recreate very well. Comparing a CD with a vinyl record in order to illustrate the difference between A and D TV is completely absurd, because an audio CD is still the analogue representation of sound waveform, just as is vinyl record is. It would be fairer to compare the vinyl record (equivalent to 1 gigabyte of data) to MP3 (typically 0.08 gigabyte). If MP3 was relased in the early 80's instead of the Philips Audio Compact Disc, it would most certainly of flopped, as magazine shelves were full of 'hi-fi enthusiasts' magazines which had articles on listening tests tonal qualities of loudspeaker cables on the most expensive gear in the world. Mass-market digital camera technology is beginning to catch up with professional camera film, (medium-format ektachrome 25 is equivalent to something like 200 megapixels). In the same way, digital TV will one day in the future not need to rely so heavily on bandwidth compression to deliver a stream, it could allow more naturally appearing movement, if more bandwidth is available. The primitive digital tv of today is currently in the dark ages, it has a long way to go yet.

A flower growing is nature's highest form of digital compression. The image of it on our retina is nature's analogue TV. Which is the best compromise of these two to project the image of a flower swaying in a breeze? The answer will always change, depending on current technology, the accountants, market forces. We are presently at the stage of manipulated computer graphics representing the flower, for HD we are increasing the number of pixels. --MarkRBarker 19:51, 20 March 2007 (UTC)

Hate to disagree with you Hpesoj00, but the driving forces to DTV includes the re-allocation of the frequencies to be used for other communications uses and addition of additional channels and ancillary services that can be transmitted by the broadcaster. HiDef HDTV development was started to increase the quality of the broadcast image to the viewer. After General Instrument, Inc. found a way to use the rapidly evolving digital technology to pack more information (pixels, bits...) into the same bandwidth of the existing channels some additional "features" came to light at the expense of being compatible with the existing television receivers. The broadcaster could transmit one really high quality image...or several with lower quality. Some even lower than current analog. Deliver several poor quality programs when the initial promise/goal was for high quality images. And Digital DTV can add additional communications data services not related to pictures or sound. The idea of "Channel 4" getting licensed to broadcast several more channels seems at the first glance to be a windfall for the broadcaster. Sadly, getting four times as many channels in a community will not generate four times the ad revenue as the population in the community stays fixed. (duh) Currently the broadcasters are running both analog and digital on different frequencies. Waste of bandwidth and electricity. Digital TV can offer images vastly superior images, but the quality can be reduced at will leading to annoying motion artifacts, quantizing/contouring artifacts noticeable in dark scenes, and image breakup should the electronics simply not be able to keep up with the data. In the end I have to agree that the page seems to tilted to being a proponent of the analog system and perhaps a POV issue could be resolved with more detailed discussion. OldZeb 06:26, 22 March 2007 (UTC)

I guess you were disagreeing with "digital is better than analog overall", I suppose it depends who you ask, it is a rather subjective topic. The section seems to have been balanced out a bit better now, but the information is still not presented in a very well organized manner. I may attempt to neaten it up if I find myself with nothing to do, but I am no master of the subject so maybe it should be better done by someone who knows what they are talking about. Hpesoj00 10:55, 23 March 2007 (UTC)

Broken link

The http://www.ee.washington.edu/conselec/CE/kuhn/ntsc/95x4.htm link is broken. It should be removed or someone should find where it has been moved to. —The preceding unsigned comment was added by 91.120.69.76 (talk) 09:54, 26 February 2007 (UTC).

Comparison of analog and digital television

Why bother? The full resolution of 525 lines (4 Mhz) on NTSC equipement has never been realized.

Well, yes it has. Many consumer receivers made in the 1990's have comb filters, some 3-D with motion compensation. A 1979 model Magnavox came with a comb filter. Ohgddfp (talk) 22:10, 27 April 2014 (UTC)75.68.228.54 (talk) 21:27, 27 April 2014 (UTC)

Most good VHS machines rarely give anything higher than 300. Even NTSC DVD players only output about 400.

The NTSC wrote the specs for analog broadcasting. So genuine NTSC equipment is actually about 340 TV lines of horizontal resolution, equivalent to 449 rectangular pixels horizontally, max. Ohgddfp (talk) 22:10, 27 April 2014 (UTC)

Even at the peak, commercial broadcasts in strong signal areas of good quality only gave 450 or so.

450 what? You talking horizontal or vertical? Ohgddfp (talk) 22:10, 27 April 2014 (UTC)

Actually gave 340 TV lines of horizontal resolution, equivalent to 449 horizontal pixels at full contrast. This is the legal limit, imposed by the FCC. (code of federal regulations, title 47, part 73, chapter 682, "Transmission standards". These are the standards, written by the NTSC and accepted by the FCC, for the specific purpose of being included in the federal regulations. Ohgddfp (talk) 16:35, 27 April 2014 (UTC)

If the system had been used to its full capacity, this may not have been so big a deal. WK 139.78.96.57 (talk) 00:20, 28 December 2007 (UTC)

One DTV channel can deliver two 4:3 640x480 resolution channels (one main and one sub) each of which is better quality than NTSC. Ohgddfp (talk) 16:35, 27 April 2014 (UTC)

Aside from the comments on POV already, with the tedious discussion above. There are a few things in this section which I don't think are true at all. A few points if I may.

Analogue and digital tv signals, in standard definition at least, are both formed of 50/60 interlaced fields per second. No difference in frame rate. I'd also query the comment on redundancy in the picture signal, an analogous representation of something is inherently redundant since it is an analogue of something and does not resemble a white noise signal which has the highest information density.

The MPEG compression used in digital TV has chroma subsampling (as do most other compressed video formats) comparable in many ways to the lesser bandwidth used for colour information in PAL/NTSC analogue signals.

The point on the uncompressed data rate of a digital signal is arguable superflous since the main argument in favour of digital television (or as far as the authorities are concerned at least) is the reduction in bandwith used. Transmitting an uncompressed signal would be impractical and pointless. Needless to say it is nowhere near as large as 250Gb/sec. Also note that 250Gb/sec does not in any way nescessarily equate to 250Ghz of bandwidth, this would depend on the modulation used and could be vastly less, though this is irrelevant anyway. I have no idea where the 250 number has come from. (Actually I think I've worked out where this may have come from now, 720 * 576 * 3 * 25 * 8 is 248832000, is about 250 Mbit/s though this assumes no chroma subsampling with 24 bits per pixel, still out by a multiple of 1000 though) (One further addition, 250Mbit/s could comfortably fit in a 6Mhz wide channel with some not too rediculously dense modulation, although this signal would not be very robust and no space would have been saved)

DTV delivers a payload of slightly more than 19 million bytes per second. Ohgddfp (talk) 16:35, 27 April 2014 (UTC)

The last paragraph should be scrapped I think also. The degredation of an analogue signal in less than perfect conditions may be more pleasant to watch but it is in no way "predictable". As far as the unpacking of audio whilst constructing a picture, the complexity of the process should not be a point against it as long as it works. In my mind the signal processing of an analogue picture is in no way simple either. (unsigned)

Comparison of analog and digital television (2)

Too many people here seem to base this article's 'facts' on what they see at home, and even drag old VHS recordings and Big Ben in to prove points. There are quite a few very subjective statements made, which have nothing to do with the true quality of digital (or analog) TV. These WK editors are blaming the Titanic for the ice berg.

Many cable and satellite stations will (re)compress digital video signals to be able to carry more data (= channels) on the same bandwidth. This obviously reduces picture quality. However, that doesn't mean digital TV is poor. It only is when it is mis-used, re-compressed, improperly transported, etc, etc, like in the example above. Just like analog signals can be distorted. The quality of digital TV is better than that of analog. There's simply no denying that. However, you can't properly judge it by watching your TV at home.

Go to a professional digital edit suite, watch the edited master on a decent studio monitor, and compare it to an analog edited master. Then you can judge what you're talking about. Jerky movement? Nonsense. Poor lip-sync? Blame your local distributor. Paint-by-numbers? Bad re-compression.

I've edited digital broadcast video for national TV for almost a decade. Do you really think we'd buy all that expensive studio hardware if digital is as bad as Wikipedia claims it is? Dudes, please... That paragraph should go. Rien Post 23:57, 6 May 2007 (UTC)

This section is virtually complete and utter nonsense. It needs scrapping and starting again. I could go through point by point but I think I have issues with everything that is currently written. Even where it says analogue transmissions are poorer than they used to be. ... and how on Earth can you compare VHS recordings and a broadcast signal? the quality of most VHS recordings is frankly ****. I'm not sure whether the fact that broadcasters have been sourcing material digitally for years would also have an affect on the ability to compare, in most cases analogue for some time has been a retransmission of the digitally sourced signal. AFAICT audio has been digital to some degree since the advent of NICAM stereo in the 80s. The claim that roof top aerials are worn out is also particular to the person - in the UK the reverse is likely to be true as many people have needed to buy new aerials to receive the comparitively weak DTT signals that Freeview is broadcast on (IIRC about 1% of the power of the analogue signal). This measure is precisely so the digital broadcasts dont interfere with the less robust analouge signal Pit-yacker 17:38, 7 May 2007 (UTC)

in most cases analogue for some time has been a retransmission of the digitally sourced signal. True, very true. Now is somebody going to delete that paragraph for good or are we editing and reverting this silly thing until the end of time? Rien Post 20:56, 9 May 2007 (UTC)

I've now removed this entire section, which was full of inaccuracies about both digital and analog TV standards, and is better off being rewritten from scratch. And yes, the whole TV production chain has been digital (and mostly compressed digital where storage is involved) for many years. -- Karada 17:44, 17 July 2007 (UTC)

Resolution

I dont really understand how an analog television broadcast can have a resolution per se, because it isn't it just like film in that it depends on what resolution you scan it at to determin the acutall resolution?Rodrigue 13:31, 24 March 2007 (UTC)

In a conventional television the picture is constructed by a scanning electron beam line by line (this is where the vertical resolution comes from). There is no horizontal resolution so to speak of in this context, although all modern television signals are from a digital source and the horizontal resolution people speak of just comes from whatever the proportional amount of elements would be required to provide the same resolution as in the vertical dimension.

There is indeed horizontal resolution with analog TV. It's limited by the spectrum space assigned to the TV station by the government regulator. This is a signal bandwidth restriction, that limits how many times the RF on-air wave can change amplitude in one second. (It is these amplitude variations that carry the picture information.) In a transmitted stream, the faster the signal can change, the closer the picture details can be to each other and still have neighboring picture details resolved (separately distinguishable) between them. In the U.S., that is the equivalent of 449 x 483 pixel resolution. Analog resolution is measured using a 1:1 square in the middle of the picture. Due to the same FCC limitation of analog broadcast stations (low power in 2014), 449x483 pixel resolution (even thought there are no actual pixels in the broadcast stream) equates to 340 TV lines of horizontal resolution and something like 330 TV lines of vertical resolution. These are how "resolution" specs in analog TV equipment are stated, although the equivalent pixel resolution is both valid and easier to understand. Ohgddfp (talk) 16:51, 27 April 2014 (UTC)

See resollution on Television talk for an attempt at an explanation.Francis E Williams (talk) 17:50, 23 November 2010 (UTC)

Ok... Cleared up a few things

Sorry for making so many edits, but I think I got this thing a bit cleared up. Some of the information is clearly made up by the person who edited it before me, but I can't find anything proving or disproving it. As for the ammount of 'citations needed', I cleared a few of them out and added a bit more info... The problem with some of the info in there is that there are absolutely no references on the internet, anywhere, it is just the way it's always been so no one talks about it. W/e, I'm done caring :P —The preceding unsigned comment was added by Gripen40k (talk • contribs) 17:39, 15 May 2007 (UTC).

Clarification needed

Can analog television owners still watch satellite and cable broadcasts with out any difficulty? Does the change only effect televisions recieving network broadcasting?Mustang6172 22:01, 28 June 2007 (UTC)

Analog television technology references needed

I've removed the analog television reference links from the University of Washington's College of Engineering as they no longer existed. Someone attempted to retrieve them from Google's cache, but the links were found to be dead when I inspected them last. Because of the fact, can anyone please cite proper sources on analog television technology that are static, no pun intended, links to information that will not be moved or removed. --Mnemnoch 07:21, 29 July 2007 (UTC)

Done! OldZeb (talk) 22:36, 3 October 2008 (UTC)

Channel allocation

How will the advent of digital TV affect channel allocations of stations already on air? WAVY 10 19:24, 24 September 2007 (UTC)

Merging/reorganising with other TV pages?

Please take a look at Talk:Technology of television. I'd like to have some discussion about possible reorganisation of the many television technology pages there are floating about.

IanHarvey (talk) 10:23, 22 January 2008 (UTC)

Proposals

Please see Talk:Technology_of_television#Proposed_Changes which I am going to implement shortly if no-one speaks up. IanHarvey (talk) 12:42, 20 February 2008 (UTC)

Merger with another Article?! I think not!

Ever seen one of these?

Analog televisions have historical significance far beyond digital, to be honest.

Some of the most important events of the Twentieth Century were on the television. The only thing that picked those things up were Analog TV sets. The Apollo moon landing and the Nixon election campaign were both on Analog TV. They had three channels with that thing (plus local stations), and for about forty to sixty years, they were happy.

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As we all know, Analog is going to be banned this June, forcing all analog owners to buy a government conversion unit.

This article should not be merged because it is a key part of the television's history. It is a highly notable article. I've seen mergers go through before, most of the information is cut out and lost to readers.

The price of those converters are fifty dollars at a Radio Shack, and they've got coupons at the Digital Transition website. These can send the price way down.

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However, analog television holds history because my father, grandfather, and ancestors watched with it, and it's one thing I, as a fifteen-year-old teenager, do not wish to see lost to history.

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My grandfather jokes about some of my generation "thinking that food comes from the grocery store,unaware of cows and farms and such". I always found that funny, but he may have a point.

As such, this is a really good article, written quite well. It is indeed notable, as aforementioned, because it was the only thing until the eighties. Cable came after. It's actually pretty much forgotton, with antennas and such being relics. This article is notable, and even historically significant.

Three channels! I don't know how I could have handled that television. My ancestors did, and that is intriging to me. This article deserves to stay for its significance, not just for me, but for all of the old people who come here.

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When I see something I love on Wikipedia (turtles, The Slowskys, ect. ect.), it puts such a smile on my face. I think all viewers, young and old, deserve that happiness of seeing something important to them sitting as an article here on the Wikipedia. It's pleasing to me.

I read to my grandfather the Super Bowl history article. He recalled it all, the article as accurate as his memory. It was an enjoyable time.

Comment Support merge with How television works, duplicate material, keep "Analog television" as title. Drawn Some (talk) 13:54, 24 May 2009 (UTC)

Merge front porch, back porch

These are 1-paragraph context-less stubs that would be better off merged here. There's a good diagram showing the definition and the cnocepts have little meaning outside of the context of a television scan line. Similarly, the synchronization material needs to be better integrated, since it is largely repetitive. --Wtshymanski (talk) 21:46, 6 October 2010 (UTC)

I have been working on these recently and was going to expand them. But if you want to merge them, then it's fine by me. It's not that important to me. -      Hydroxonium (talk) 05:01, 8 October 2010 (UTC)

The more I look at this article, the more work it needs. Where's the *transmitter* end? Never mind the microseconds, etc. but we don't talk about the limitations and defects of analog transmissions, and *why* they are being phased out. Typical Wikipedia myopia...list all the engine model numbers but never explain *why* you need a train. --Wtshymanski (talk) 17:00, 12 October 2010 (UTC)

Oppose Front and back porches have almost nothing with analog TV. The porches are certains portions of the VF signal. If this much is sufficient for the merging, than everything related to VF signal should also be merged to Analog TV like sync pulse, chrominance, black level, luminance, frame (video) etc, etc. Then by this logic, why do we leave out the AF signal.Nedim Ardoğa (talk) 09:40, 9 November 2010 (UTC)

Isn't that kind of the point? Analog television is the broadcasting of analog TV signals, which have front porch, etc. components. Everything describing an analog TV signal should be in one place and not scattered in context-less fragments. (This also needs more references.) --Wtshymanski (talk) 14:13, 9 November 2010 (UTC)

I agrre to oppose the merger, on the basis that the control signals required for digital display of coded data are still required, and are part of the current digital transmission signals. These still control the positioning of scan lines on the display. Try this link, you`ll have to buy the document to view the content about front and back porch detail.Francis E Williams (talk) 21:04, 23 November 2010 (UTC)

Citations / References / External links

I trained in, and qualified in Television and Electronics. I worked with analogue (English) /analog (Amaerican) television technology since 1963. From days of valve projection single channel receivers to todays flat screen LED (not LCD) displays. (Have 42" Panasonic LED TV.). I`m a bit of a "techie" in many fields...Plus .. I`m retired, makes me a good candidate to spend this winter exercising the dying "grey cells", (and the failing eyes), to add the refs. and my knowledge to this fine article.Francis E Williams (talk) 21:19, 23 November 2010 (UTC)

Power supply

I correctly included power supply design to augment the section entitled Power supply. I note that you have removed this contribution and have renamed the section CRT power supply now. Had this been correctly labled in the first instance I would not have added any material about the DC supplies for Analogue Television. This added content is SPECIFIC to analogue TV development and design. The EHT voltage multiplier is correctly named and is attributed to Cockcrofts design. Having been technically qualified in this field for over 47 years I can speak with some competence and authority on this subject. This technically oriented article is going to have little merit and credibility without accurate and verifiable content. If it is to be an Historical article, then it will require Historical verifiable content. See WP:OWNFrancis E Williams (talk) 21:52, 23 November 2010 (UTC)

If you do not want your writing to be edited, used, and redistributed at will, then do not submit it here. THis used to say "ruthlessly edited" but we grow soft. You're perfectly at liberty to set up the Francis E Williams "I've got 47 eyars experience and know better than you" wiki of your own. In the mean time, welcome to Wikipedia. A long diatribe on power supply design is not important to the analog television article; there's a power supply article for that. --Wtshymanski (talk) 21:57, 23 November 2010 (UTC)

That is not the impression I wish to give. You completely mis-interpret my declaration of qualifications. It is nothing about "being better than you". I just wanted you to understand my contributions will be technically accurate and in accordance with Wiki style policies. The article contains all the salient "daitribe" as you put it about all the other sections of a television receiver, so why skip out the power supply section?. Is there a link in the article to it? Why bother with the CRT power generation either? The article has been copy edited, the content is still the same, but it is now more logically ordered. Thank you for your welcome to Wikipedia, I have only been contributing to and creating articles during the last 15 months or so. It is my intent to improve the article .. not take it over. Rather than "edit war" with me, why not discuss any help I can give you. I will not be around for much longer on Wiki, (See my user page). i cannot teach experience to you or anyone else. I can only share with you what I have learnt in my lifetime about various subjects.Francis E Williams (talk) 23:25, 23 November 2010 (UTC)

With the power supply discussion, the question to ask yourself is, how many of these methods also apply to other technologies, such as radios or phonographs? The simple rectifier and thyristor supplies were probably common in non-TV devices too, so discussion of these is probably more appropriate over in the generalized power supply article, with maybe a brief mention in the TV article but steering readers over there for more detail.

The one supply that really is TV-specific is the horizontal deflection power supply. It's been many years since I looked at a TV repair book but I seem to recall that many TVs used the horizontal deflection circuit as the main power supply for everything else.

DMahalko (talk) 02:07, 24 November 2010 (UTC)

Valid point, the "Syclops" synchronous power unit was designed by BRC (Thorn) for Television. The linear (240v mains dropper) power design eliminated the requirement for a mains transformer as all valve T.V. H.T. circuits were around 200v. Valve heaters were cascaded (daisy chained) from the A.C. mains, CRT heater being the last in the chain. May I suggest leaving these in the article and in the section add {{main article - power supply}}? That would fix it. The only other known occurence for a mains dropper was in cheap 240v mains radios, where a resistance wire was used in the mains supply lead. If reduced in length (by some people) the set received too much current and this resulted in premature failuer. There were other synchronous thyristor commutating power designs made for wide angle <110 deg. deflection (Finlandia range of TV) but these were not popular as timing errors destroyed much circuitry when failure occured. I could bore you for ever with the technical issues involved, but the point is this:- The article attmpts many things, Historical and Technical, but a lot of what it contains relates to modern current practice in broadcast engineering. The reader can skip over the bits that are not relevant, but to leave out important parts in a "stand alone" article is like describing how a car works and leaving out the engine!. Hope I can help with this interesting subject by providing some "staircase" waveforms showing the actual relationship between the luminance and chroma signals as produced by a colour bar generator. Regards,Francis E Williams (talk) 10:39, 24 November 2010 (UTC)

About the "ENGINE", which could be the power supply: Remember that this article is titled "Analog Television". I think the reader expects things that are unique to analog TV, plus some context. A reactive magnetic deflection CRT scanning system actually drove some particulars in the FCC approved 1941 analog TV standards signal format. Therefore a reactive magnetic scanning system should be briefly described only to the extent to show where the analog TV signal standards came from. Explaining any more detail is problematic because the same power supply articles in great detail would need to be placed in all kinds of TV technology articles, including some digital television receivers also using CRTs with reactive magnetic scanning. One in black and white TV, another in color TV, another in digital TV, another in video computer monitors that displayed only text, and so forth, all using the same basic reactive magnetic scan CRT technology. The idea of an encyclopedia is not to put identical in-depth articles in many places; it creates an index or method of searching that the reader finds cumbersome and confusing. In short, the simplified version needs to be here, but an in-depth version needs to appear in only one place on its own. Ohgddfp (talk) 00:45, 3 May 2014 (UTC)

Article layout and readable continuity

I have at last stopped being a "Techie" based editor with this article. I now think the article should focus more on the differences in image processing aspects of analog transmissions, rather than the technological changes that have taken place with the hardware. Some historical hardware detail has to be included of course, to make the article more complete, more accurate, and informative to the technical reader. Should this be the way forward with this article, if so what do you think? I quote this rather observant editors comment, "after a few years of accretion someone has to go through and bubble-sort everything to put it into some logical sequence".Francis E Williams (talk) 22:00, 25 November 2010 (UTC)

Yes, mostly. About hardware. Hardware to the extent that it informs how the analog video signal format came to be. Limitations and expense of receiver hardware had a huge effect on the engineering choices of the analog signal format particulars. Ohgddfp (talk) 00:50, 3 May 2014 (UTC)

Red over-saturation / bleeding?

Can there be a section discussing the problems with red over-saturation in NTSC video? I know that intense red is not handled well, and can lead to smearing/bleeding of the red across the scan line. There is probably a technical explanation for it, but I am not enough of an expert to talk about it. DMahalko (talk) 18:32, 22 December 2010 (UTC)

In some scenes with red lettering, for example, red can seem to bleed. But this is rare. Red bleeding in general always happens if the receiver saturation knob is set incorrectly high, which is probably where this picture quality complaint comes from. Ohgddfp (talk) 16:58, 27 April 2014 (UTC)

Vsync

Vsync redirects to this article, but it does nothing to answer my question. I'm trying to learn what the setting I see in numerous PC games does and what are the (dis)advantages to enabling it.--69.110.0.210 (talk) 01:32, 31 January 2011 (UTC)

Hello, I might be able to help here. First what do you mean by "sync"?. Gaming performance on a P.C. improves by making the picture change faster to make it appear more realistic.

1) Graphics processors are usually mounted on a seperate adaptor card with large memory area to store visual data. The faster you set the "refresh rate", (the vertical "frame rate" 60, 75, 80hz etc.), the quicker the picture is drawn on the display. More memory is required the faster you go. If you could alter the "Vsync" timing signal, all you would see is a black line with no picture in it at either the top or bottom of the screen.

2) Colour depth - v - Frame rate. If you display your gaming picture faster, your graphic chip might not keep up with the demand to chanage the memory contents so quickly. If you reduce the colour depth from 32 bit (true colour), to say 16 bit, only a quarter as much memory is required to be used, so the picture can be drawn faster. (a 16 x 16 grid has one quarter of the squares that a 32 x 32 grid has).

So, in conclusion, you graphics processor has finite resourses available to it. A good performance compromise is 75 hz field rate, 24 bit colour depth, display resoloution of 1024 x 768 pixels. Any decent modern graphics card will handle that ok. Hope this helps. Francis E Williams (talk) 14:01, 31 January 2011 (UTC)

A contradiction

This article contradicts the article on Digital television transition. The latter article states that the Netherlands was the first country in Europe to switch to digital television, but this article states that it was Luxembourg. ACEOREVIVED (talk) 00:30, 24 February 2012 (UTC)

Color video signal extraction - Edit

In the section, "Color video signal extraction", I would like to see a change to the paragraph that begins with "Instead, the RGB signals are converted into YUV form, where the Y signal represents ...". The new version I believe clears up some details by using well documented technical facts. Here's the new version: Ohgddfp (talk) 16:22, 27 April 2014 (UTC)

Instead, the RGB signals are converted into YUV form, where the Y signal represents the lightness and darkness (luminance) of the colors in the image. Because the rendering of colors in this way is the goal of both black and white (monochrome) film and black and white (monochrome) television systems, the Y signal is ideal for transmission as the luminance signal. This ensures a monochrome receiver will display a correct picture in black and white. The U and V signals are "color difference" signals. The U signal is the difference between the B signal and the Y signal, also known as B minus Y (B-Y), and the V signal is the difference between the R signal, also known as R minus Y (R-Y). The U signal then represents how "purplish-blue" or its complementary color "yellowish-green" the color is, and the V signal how "purplish-red" or its complementary "greenish-cyan" it is. The advantage of this scheme is that the U and V signals are zero when the picture has no color content. Since the human eye is more sensitive to errors in luminance than in color, the U and V signals can be transmitted in a relatively lossy (specifically: bandwidth-limited) way with acceptable results. Ohgddfp (talk) 16:22, 27 April 2014 (UTC)

Different combinations of U and V can be directly extracted in the receiver using demodulator circuits. For example, the RCA Victor CTC-4 chassis used one (R-Y) demodulator circuit and one (G-Y) demodulator circuit. The (B-Y) demodulator circuit was done away with, and so the (B-Y) signal was derived by electronically combining the (R-Y) and (G-Y) signals in a particular combination. Other schemes, including (R-Y)/(B-Y), (R-Y)/(B-Y)/(G-Y), I/Q, (R-Y)/Q, and various flavors of X/Z were used. In all cases, (R-Y), (B-Y), and (G-Y) are all recovered in the end. Ohgddfp (talk) 16:22, 27 April 2014 (UTC)

The R,G,B signals in the receiver needed for the display device (CRT, Plasma display or LCD display) are electronically derived by matrixing as follows: R is the additive combination of (R-Y) with Y, G is the additive combination of (G-Y) with Y, and B is the additive combination of (B-Y) with Y. All of this is accomplished electronically. It can be seen that in the combining process, the low resolution portion of the Y signals cancel out, leaving R,G, and B signals able to render a low-resolution image in full color. However, the higher resolution portions of the Y signals do not cancel out, and so are equally present in R, G, and B, producing the higher definition (higher resolution) image detail in monochrome, although it appears to the human eye as a full-color and full resolution picture. Ohgddfp (talk) 16:22, 27 April 2014 (UTC)

Structure of a video signal - Intercarrier - Edit

About "The carrier is never shut off altogether; this is to ensure that intercarrier sound demodulation can still occur.": This is a fallacy. The reality is that not allowing the carrier to go below 15 or 25 percent for the white reference (minimum picture carrier) was being pushed back in 1941 and even earlier. The Intercarrier sound recovery technique was invented in 1944/1945. There is an 1948 patent on intercarrier sound. But this fallacy goes even further. You don't need an on-air continuous picture carrier to use the intercarrier sound recovery technique. Let's say reference white was standardized at zero percent carrier. In a movie about a snow storm, you will have a frequency spectrum that includes the carrier and sidebands. If inside the receiver the picture carrier is narrow-band filtered to less than 30 Hz, the flywheel effect of the filter would produce a continuous picture carrier at the filter output from the intermittent picture carrier received over the air. The new continuous picture carrier would then be applied to effect the intercarrier operation, producing a clean 4.5 MHz sound IF. To fix this in the article, I would simply remove the sentence. Ohgddfp (talk) 21:56, 27 April 2014 (UTC)

Analog - what is it?

The very first paragraph has a problematic phrase: "... one in which the information to be transmitted, the brightness and colors of the points in the image and the sound waves of the audio signal are represented by continuous variations of some aspect of the signal; ...". The problem is that the exact same thing can be said of 8VSB digital television. On the air, the DTV signal is a continuous-time signal. But one might say that the DTV signal represents a discrete-time list of values streamed over the air, which it does, and so the continuous-time on-air signal and the discrete-time digital signal inside the digital receiver both represent the same information. But that doesn't distinguish analog from digital either, because any real analog signal also represents a discrete time list of values, where both discrete-time analog and continuous-time analog represent the exact same information. To find out what exactly that discrete time list of analog values are, just sample the continuous analog signal. The result is analog (not digital) samples.

So what makes an analog signal analog? At any given point in time, an analog signal can take on any one of an infinite number of possible values.

So the sense of the word "continuous" as used in the opening paragraph to mean continuous-time, does not distinguish analog from digital. Rather, it is "continuous" in a very different sense that makes the difference. And that requires a different explanation. The value of each analog sample is continuously variable, meaning that its value is taken from a continuous range of possible values. That means an analog sample can take on any one of an infinite number of possible values, or the possible value of a single given analog sample is infinitely or continuously variable. In contrast, a digital sample can be any one of only a limited number of possible values. So here is the recommended fix:

Analog (or analogue) television is the analog transmission that involves the broadcasting of encoded analog audio and analog video signal:[1] one in which the information to be transmitted, the brightness and colors of the points in the image and the sound waves of the audio signal are represented by some aspect of the signal; its amplitude, frequency or phase, the values of which, at a given point in time, is any one of an infinite number of possible values. Ohgddfp (talk) 02:28, 29 April 2014 (UTC)

Analog doesn't have to do with continuous/discreteness, but with analogness, as in analogy. In the case of video, some property such as voltage, current, density, magnetic field strength, frequency, or probably others, changes in relation to the luminance in the source. Because we live in a quantum world, most of those are actually not continuous, but that isn't important. (Voltage is quantized by the charge on the electron and capacitance of the system. V=q/C) Consider a text display that is black and white, but no gray. It is discrete, but in an analog system sent as a voltage with two possible values. In the digital case, it is numbers that are transmitted, not voltages or currents. Gah4 (talk) 15:17, 25 March 2020 (UTC)

CRT flyback power supply design and operation principles - Doesn't belong here

Wide screen 16:9 aspect ratio CRT-based receivers were available for a while for reception of digital television signals. So flyback power supply design, which is specific to CRT-based receivers, applies equally to analog and digital. Since the title of this article is "Analog Television", the reader expects information that is unique to analog. This section is so long that a link to flyback power supply design by far makes the most sense. I'm planning to move it to the appropriate article. Ohgddfp (talk) 02:22, 30 April 2014 (UTC)

CONFUSION BETWEEN "TV SYSTEM" and "COLOR SYSTEM" !

There is --- maybe in all the english Wikipedia articles ? --- a confusion between the system of transmission and the color coding.

The official systems of transmission are named : A, B, C, D, E, F, G, H, I, K, K1, L, M and N. These systems determine the Number of lines, Channel width, Vision bandwidth, vision/sound separation, etc.

The colour coding which may be used of those systems are NTSC, SECAM and PAL.

So, I'm sorry for Wikipedia but this is the official situation.

--AXRL (talk) 14:25, 9 May 2014 (UTC)

Rename article to Analog (Analogue) Television Systems

Just finished skimming the article and I agree that it should remain as a summary of the different types of transmission and reception systems which were in use. That being said, the words Television and TV generally refer to the receiver in American English. Renaming the article to Analog (Analogue) Television Systems would inform both American and Commonwealth English readers that this is a general overview article with links to more in-depth articles.Divercth (talk) 21:35, 29 January 2015 (UTC)

This is not supported by WP:TITLE (where parenthetical disambig is allowed after the main title, but not within) nor WP:ENGVAR. It would make for an awkward title. We don't follow this practice for any other articles I'm aware of, like Analog recording, Analog computer, Analog synthesizer, etc. There's already a redirect - "Analogue Television" redirects here. And the redirected term "Analogue television" is bolded in the lede. This is in accordance with WP:ENGVAR. Jeh (talk) 22:20, 29 January 2015 (UTC)

Standards

About a particular existing paragraph in "Standards": Ohgddfp (talk) 16:52, 21 March 2020 (UTC)

"For this reason many people refer to any 625/25 type signal as "PAL" and to any 525/30 signal as "NTSC", even when referring to digital signals; for example, on DVD-Video, which does not contain any analog color encoding, and thus no PAL or NTSC signals at all. Even though this usage is common, it is misleading, as that is not the original meaning of the terms PAL/SECAM/NTSC.": Ohgddfp (talk) 16:52, 21 March 2020 (UTC)

I would replace it with the following 2 paragraphs: Ohgddfp (talk) 16:52, 21 March 2020 (UTC)

For this reason many people refer to any 625/25 type signal as "PAL" and to any 525/30 signal as "NTSC", even when referring to digital signals which actually do not have these type signals in original form. However, those digital signals do have some commonality with those analog "NTSC" and analog "PAL" formats because when the digital signal is directly converted to an analog signal, digital "NTSC" and analog NTSC both have lines and frame rates as 525/30. The same is true for PAL, with digital and analog versions both having lines and frame rates as 625/25. This is important because all but "international" analog Televisions/Monitors work only with analog NTSC or analog PAL, but not both. So DVD players, where most digital "NTSC" and digital "PAL" signals come from, have a corresponding analog NTSC or analog PAL output connector for connection to an analog TV/Monitor. A given DVD player does not have both kinds, so the analog TV/Monitor must match up NTSC or PAL to the DVD player, or a scrambled picture, and/or loss of color is the likely result. Ohgddfp (talk) 16:52, 21 March 2020 (UTC)

When using certain kinds of digital equipment, with no analog equipment involved, digital format conversions can and usually do take place. The conversion can increase or decrease the number of pixel rows (lines), change the frame rate, and convert from interlace scan to progressive scan, making the designations of "NTSC" or "PAL" almost meaningless to the consumer, except that "NTSC" or "PAL" indicates to the consumer a picture quality that has a hard limitation in vertical resolution. Both kinds of conversions to a new digital format, from digital NTSC or from digital PAL, do not always give perfect picture quality, and years ago, such converting equipment was expensive in hardware, and very demanding in computer resources as digital software. Ohgddfp (talk) 16:52, 21 March 2020 (UTC)

None of this, original or your proposal, is cited. Expanding it further per your proposal would appear to be original research. ~Kvng (talk) 14:32, 24 March 2020 (UTC)

Yes. So I agree that my 2 paragraph explanation would need citations. And I should have mentioned (sorry) that those 2 paragraphs are not exactly my proposed changes, but instead only represent the idea content that I propose. I think the term used in the article, "misleading", is not really the case. The proposed inclusion of content would say "potentially confusing" instead. But that opens up questions in the reader's mind as to why the market uses such confusing terms. And my idea suggestions (as to content), tries to answer that question. I would like to come to agreement as to the content, with challenges to specific claims so we can discuss each of my assertions and to help me find citations for them. This should lead to the citations I haven't yet found, because I believe my claims are in the main stream on this topic. Some of my claims are actually restatements of text elsewhere in this article. Most of the rest are straight forward mainstream science common sense conclusions of these assertions. Ohgddfp (talk) 05:00, 25 March 2020 (UTC)

With a sample size of two, my WP:OR shows one DVD that says NTSC and one that doesn't, but both say Region 1. Since region 1 is NTSC land, there will never be a problem. I would expect 625/50 (field rate) to say PAL/SECAM as both would match those rates, but in that case my sample size is zero. So, the problem only comes up in regionless DVDs, which I believe exist, but I don't have any. TV that I used to have, had a switch which I believe allowed it to do 50Hz field rate, such as might be generated by an NTSC DVD player playing a 625/50 disk. The bits will still come out NTSC encoded, the line rate is close enough, so all it needs to do is adapt to a 50Hz field rate. What do DVDs in other regions say on them? Gah4 (talk) 15:05, 25 March 2020 (UTC)

About "as might be generated by an NTSC DVD player playing a 625/50 disk": If your "NTSC DVD" player could play a 625/50 disk while outputting a 525/30 analog signal, that means it had a built-in digital standards converter. This kind of conversion is very difficult to carry out with good picture quality (easy if bad picture quality is OK). While the similar line frequencies would be easy to take care of, the different frame rates are very tough and expensive to deal with if picture quality and smooth motion are important. If such a unit had this standards converter, I'm fairly sure it would not simply be an "NTSC DVD" player. It would be known as an "international" or "dual standards" model (or something like that). More likely, when the DVD player played an NTSC disk, it put out an analog NTSC signal, and when playing a PAL disk, put out an analog PAL signal. In that case, no standards conversion is needed. Ohgddfp (talk) 01:30, 26 March 2020 (UTC)

The TV I had was older than DVD, so I believe it was designed for laser disk. 625/50 is 15625Hz line rate, not so far from 15734Hz. The switch let the vertical oscillator go to 50Hz instead of 60Hz. But the color subcarrier is NTSC form. I never had a player to test it on, though. Gah4 (talk) 04:40, 26 March 2020 (UTC)

Given that South America is region 4, but "NTSC" or "PAL" are in neighbouring South American countries, it is easy to have the "wrong" TV or monitor. So both the region number and the video standard are helpful for matching up to the correct TV/monitor. Also, before the regionalization of DVDs, TVs and monitor were sold as "NTSC" or "PAL", so such designation on the older DVD players with analog-only outputs made it the easiest way for consumers to match up the right equipment. Ohgddfp (talk) 01:30, 26 March 2020 (UTC)

Not living near those countries I don't know, but I suspect that many people in those countries have multi-standard TV sets. If they are close enough to get broadcast signals, they would want them, in addition to tape or disk players. I suspect also that it isn't unusual for multi-standard sets to decode mixed standard signals, such as 625/50 NTSC. Gah4 (talk) 04:40, 26 March 2020 (UTC)

This one describes the TV set that I used to have, with a switch to work with PAL/SECAM VHD video disk players. Not having one, I don't know so much about them. I am pretty sure the TV doesn't have a PAL or SECAM decoder. Gah4 (talk) 04:51, 26 March 2020 (UTC)

The [https://elektrotanya.com/goldstar_cf25c26_cf29c26_multi-26-systems-chassis_mc51b_sm.pdf/download.html Goldstar CF25C26 does 26 different standards, including NTSC/3.58/50. Also NTSC4.43MHz, that is, like NTSC but with the chrominance subcarrier at 4.43MHz. Also PAL with 60Hz field rate. With the corresponding DVD and VHS players, this is what someone in those countries you mention would want. Gah4 (talk) 05:41, 26 March 2020 (UTC)

moderately?

The article says: Thus with analog, a moderately weak signal becomes snowy and subject to interference. In contrast, a moderately weak digital television (DTV) signal and a very strong digital signal transmit equal picture quality. Depending on the definition of moderately, this is true. The problem is that moderately weak might be below the ability to decode, in which case you get nothing, or, more usual, flashing on and off, as it does, and then does not, have a decodable signal. With analog, it gets weaker and snowier. This is well known, and part of come FCC rules, as there are places that had a strong enough analog signal, but too weak in digital. Gah4 (talk) 21:35, 20 May 2020 (UTC)

I have improved this. ~Kvng (talk) 13:56, 23 May 2020 (UTC)

variation, or not?

The article says: brightness, colors and sound are represented by rapid variations of either the amplitude, frequency or phase of the signal. This doesn't seem quite right. A given brightness or color is represented by an amplitude, frequency, or phase. Rapid change in brightness or color by a rapid change in those quantities. The screen can be one brightness and color, in which case the amplitude, frequency, or phase is not changing. Sound, on the other hand, is always represented by something changing, though maybe not so rapidly. Some might say that 20Hz isn't rapid. Gah4 (talk) 21:41, 20 May 2020 (UTC)

Even if the picture is boring, the analog signal is still rapidly changing as the raster is scanned. At minimum there's always the ~15 kHz horizontal sync. ~Kvng (talk) 13:58, 23 May 2020 (UTC)

I was considering 15kHz not rapid, in the 4.2MHz bandwidth, but the point was that a specific brightness or color is represented by a specific ampitude, phase, or frequency, not its derivative. That is, not on how fast it is changing. As noted, this is not true for sound, where a constant sound is represented by changing something. Gah4 (talk) 21:09, 23 May 2020 (UTC)

OK, I get it. I have removed the rapid variations bit and added a link to Instantaneous phase and frequency. This is arguably a dumbing down but this is the lead so we don't need to feel obliged to cover all wrinkles here. ~Kvng (talk) 12:51, 26 May 2020 (UTC)

Computer CRTs

Quote from article "Horizontal and Vertical Hold controls were rarely used in CRT-based computer monitors", This is patently wrong. Most monitors from a CBM PET to a TRS-80 model 4 to a DEC VT420 to a IBM 5153 monitor, all have both sync controls. Some accessible without removing the case, some only as maintenance controls, but they still had them. — Preceding unsigned comment added by 192.149.117.67 (talk) 04:44, 31 July 2020 (UTC)

Problems with the diagrams

I am looking at the diagram and comparing it with the image of the oscilloscope. They appear to contradict each other. The diagram puts the "rear porch" in front of the line of signal, whereas the same area is labelled "front porch" on the oscilloscope image - which seems more likely to be correct. Additionally, the illustration has a hue that changes from reddish to greenish along the line and is labeled "chroma", but I'm fairly certain that is not how chroma works and the color is more defined by the width of the lines. Further, the color burst has a similar change in hue, but is the color burst not a single frequency? Maury Markowitz (talk) 21:45, 19 May 2021 (UTC)

I added a reference with the naming of the porches, to be sure. It seems slightly more obvious to name porches relative to the visible line, but they seem to be named relative to the sync pulse. Either that, or someone's house is backwards. I didn't change any text to agree, though. As far as frequency, technically it isn't a single frequency as it has finite duration. But yes, the coloring doesn't describe anything related to the signal. I don't know why it has that coloring. Gah4 (talk) 01:10, 21 May 2021 (UTC)

...unpleasant side effects

@Kvng: I'm pretty sure the effects being referred to in the text you removed in this edit are mostly flesh tone problems, although I can't immediately find a source for that. What certainly can be sourced is that the NTSC system suffered from this problem, so much so that North American sets were commonly fitted with a "flesh tone" knob to allow the user to correct the picture. RGB with its much wider bandwidth would be much more susceptible to channel attenuation differences than NTSC. The PAL system largely overcomes this issue and Brit engineers rudely referred to NTSC as "Never Twice the Same Colour". SpinningSpark 10:40, 16 March 2022 (UTC)

Well, yes some sort of color error. But baseband RGB interfaces don't seem to have this problem. I don't think it is necessary to talk about speculated weaknesses of an implementation that I don't believe was never given serious consideration because of backwards-compatibility issues.

NTSC color problems are due to colorburst error. PAL fixes this by inverting the colorburst on alternate lines so the error can be canceled. I believe later NTSC systems had a way to correct this. ~Kvng (talk) 23:45, 16 March 2022 (UTC)

Yes, phase error between the colourburst reference and the colour sub-carrier was the primary issue. However, amplitude difference between the two sub-carrier sidebands was also significant. I had a source for that when I posted yesterday – I'll try to find it again if you want. But I agree, this is not important to discuss in the article, RGB in three contiguous bands was not a system ever attempted, and colour error was not the primary reason for not using it. I just wanted to comment that there might have been something behind the contribution beyond vague hand waving. SpinningSpark 15:10, 17 March 2022 (UTC)

amplitude, phase and frequency

The article says: amplitude, phase and frequency. For US NTSC, video is amplitude and phase, but audio is frequency (FM). That wouldn't be so bad, but the link is to phase and frequency as one article. I believe some system(s) use FM for video, though. Can we have separate links for phase and frequency? Gah4 (talk) 20:51, 6 April 2023 (UTC)