Talk:Digital television

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Wiser Proposal

Proposal to improve a Wikipedia article as required for my NJIT Technical Writing course.

Wikipedia Article Topic: Digital Television

APA citation for the Wikipedia article: Digital Television. (2012, April 6). In Wikipedia. Retrieved April 7, 2012, from http://en.wikipedia.org/wiki/Digital_television

Wikipedia Definition:
Digital television (DTV) is the transmission of audio and video by digitally processed and multiplexed signal, in contrast to the totally analog and channel separated signals used by analog TV. Many countries are replacing broadcast analog television with digital television to allow other uses of the television radio spectrum.

Proposal:
I decided to work on this article because Digital television(DTV)is a service that we can appreciate and enjoy today because of the work of many engineers. As I skimmed through the article I notice that the article lacks information and that the definition itself could be more detailed. Digital Television is just one of many topics of high importance in the Telecomunication. As an Electrical and Computer Engineering Technology (ECET) major at NJIT and I believe my contribution will improve this article. I will be expanding the definition of Digital Television and adding information on the four DTV standards worldwide.

Supporting Sources:
Kruger, L. G. (2001). Digital Television: An Overview. Hauppauge, New York: Nova Publishers.
Ong, C. Y., Song, J., Pan, C., & Li, Y.(2010, May). Technology and Standards of Digital Television Terrestrial Multimedia Broadcasting [Topics in Wireless Communications], Communications Magazine, IEEE , 48(5),119-127
(MGarcia09-NJITWILL (talk) 17:59, 14 April 2012 (UTC)

Comment

Can someone include frame rate information. —Preceding unsigned comment added by 67.167.251.140 (talk) 04:09, 9 January 2011 (UTC)

Protection parameters

This table could do with some explanatory preamble. I'd write some, but I'd probably make a hash of it. richi 19:07, 24 July 2007 (UTC)

That table is missing references: who did the measurements? I think it was purposely inserted in the article in order to build an opinion on something. But I've got no evidence of it. --Cantalamessa 14:48, 25 July 2007 (UTC)

Universal standardization

From the article:

However, the world could not agree on a single standard (why?)

Chauvinism, short-sighted (and self-defeating) greed, stupidity, not-invented-here syndrome, politics. This is one of the very few areas where I belived that Microsoft got it right: namely, that the TV bitstream should be resolution-independent, and few tens of thousands of transistors should re-format it to fit the display device raster at the end of the display pipeline at a cost of around $0.01 per unit. However, the TV manufacturers and hardware manufacturers didn't want to lose face / market share to M$, so they (in my opinion) shot their own standard in the head to spite MS. -- The Anome 14:09 19 Jul 2003 (UTC)

I agree with your first sentence, but I can assure you that you cannot create a $0.01 device to perform standards-conversion on a television signal. The combination of interlace and different field-rate standards make the problem a total nightmare. Professional standard-converters are rack-mounted devices that can cost tens of thousands of dollars and still produce results that are distinctly lacking when viewed critically. -- elvum 10:32 28 Mar 2005 (UTC)

Articles that follow each deployment domain?

Should each geographical domain have its own page for this subject? There's a lot more to be said about this subject, but readers in one geographical location might not be interested in all the details of the other areas. - Bevo 15:49, 16 Mar 2004 (UTC)

---

" As of November 2003, only one Canadian television station, Citytv in Toronto, broadcasts a regular digital television signal."

What?? I subscribe to digital TV and I have hundreds of channels so there are way more than just CityTV! SD6-Agent 10:53, 30 Apr 2004 (UTC)

What you have is digital cable. CITY's broadcast (over-the-air) signal is what is being referred to here. –radiojon 04:33, 2004 May 3 (UTC)

Clarification needed

What do you really mean by digital terrestrial television? Is is the same thing as FTA digital television? From User: DanCBJMS, 17:24 American EST, 13 February 2005

No - It just means that the transmitting antenna is attached to the Earth (i.e., that it is not extra-terrestrial - as in a satellite).

Also, in the United Kingdom a television broadcast must be available to more than 98% of the viewing population to be classed as terrestrial. For this reason, broadcaster Channel 5 is not classed as terrestrial as only 95% of viewers are able to receive it. --Dazzla 12:48, 5 January 2006 (UTC)

In general "Digitial Television" includes transmission from Terrestrial towers, Satellites, Cable and must recently mobile systems. This suggests that the "top" article should be "Digital Television" (which in turn is under "Television" and then we have the different transmission systems (each of which typically has its own regional standards and own, but competing, markets. --Alistair9210 08:48, 4 July 2006 (UTC)

In the technical section the article indicates IPTV is delivered with Quality of Service (QoS). I don't understand how that can be done over the Internet since IP is potentially lossy. Is there a retransmit protocol that is included with IPTV that makes this possible. The IPTV article does not mention QoS. Jbottoms76 17:03, 27 March 2007 (UTC)

Sorry, you many not understand it, but it's true.

Also, Digital Television, in addition to including Terrestrial towers, Satellites, Cable, and mobile devices, should probably include wired devices including SDI and IPTV, as well as other stuff. —Preceding unsigned comment added by 64.229.108.38 (talk) 21:01, 2 November 2008 (UTC)

Some question

I came across this article that seem to imply that electronics vendors were the reason behind the huge choice of digital TV format. See the quote below "Why 18 digital-TV formats if so few are used? Much of the consumer-electronics industry remains stuck at a kindergarten-playground level of conflict resolution; when the Federal Communications Commission had to pick a standard in the mid-1990s, embracing all 18 formats available was the best it could do." Is this really true? I read somewhere else that it was entertainment suppliers who contributed to the mess. [1]

When the two big digital TV systems (ATSC and DVB) were introduced and devised, they were designed so that they can be universal in the sense that there wouldn't be the NTSC/PAL/SECAM mess and no mess with the mains power supply, which is how most of the old analog television systems were governed by (60 Hz (which invariably meant using NTSC, except in a few situations where PAL-M and PAL-N are used, especially in South America) vs. 50 Hz (which invariably meant using either PAL or SECAM)). The mains power supply in turn dictates frames per second for each TV system, whereas in the movies 24 frames per second is the norm. If you look at the ATSC system, for instance, some of the formats, yes, aren't that different (SDTV-wise) from NTSC sets (480i and 480p (the so-called EDTV)), but there are also formats for the other TV standards (576i and 576p) and there is even a 1080p standard that film companies can use (because this 1080p standard is 24 frames per second). I am positively sure that DVB is somewhat the same way. However, of course you have the bickering that often ensues which also involves politics, and thus most (not all) countries with NTSC systems will most likely use ATSC, while everywhere else will most likely use DVB. Thus, this makes the other formats (576i and 576p) obsolete. Whether the film companies will bank on the other ATSC or DVB standards that are designed for their film projectors (that invariably use 24 frames per second) remains to be seen. -Daniel Blanchette 19:42, 26 February 2006 (UTC)

Could we get part of that into the article? I'm especially thinking of NTSC/PAL/SECAM vs. Digital television. I cannot read clearly from the article that the digital television standards would replace them. Mlewan 17:14, 14 March 2007 (UTC)

Note that there is sound evidence that the "NSTC/PAL/SECAM" mess was created on purpose to protect national TV industrials. The same

is true for ATSC, it was a format created to protect the US TV industry. It's a fascinating story. —Preceding unsigned comment added by 64.229.108.38 (talk) 21:04, 2 November 2008 (UTC)

Section 2.1 is US-centric

From the article:

"Terrestrial DTV is widely seen as an example of a technology that is being pushed on a public that does not exhibit much demand for it. This is particularly so for high definition (HDTV) broadcast, where HDTV sets are at the moment prohibitively expensive, and very little HDTV content exists apart from movies."

I think the first sentence may hold true for the USA, but it's arguably not true in the UK, where Terrestrial DTV has proved surprisingly popular. One of the reasons is the UK standard (as in most European countries) is not HDTV-based, but SDTV and wide-screen based. Most people have bought cheap plug-in terrestrial DTV 'adapters' costing less than a £100 to get the extra channels available. Also, a TV set with an integrated digital terrestrial TV tuner now only costs an average of around £50 more than an equivalent non-digital TV set.

It's also not true that very little HDTV content exists apart from movies. The Japanese, who've had HDTV longer than anyone else, have squillions of hours of the stuff in all sorts of genres, including music, documentary and sports, and a considerable amount of the BBC's production is now being shot in HDTV - not for the UK market, but for markets like the USA and Japan which increasingly won't purchase TV content from abroad unless it's HDTV format.

Eh? The DTV system used in North America isn't HDTV-based. [2] It can carry HD signals, but SDTV ATSC exists and will most likely be the standard until HDTV monitors and tuners become cheaper. --/ɛvɪs/ /tɑːk/ /kɑntɹɪbjuʃ(ə)nz/ 20:25, July 10, 2005 (UTC)

I also bumped into this on Slashdot: http://www.pbs.org/opb/crashcourse/digital_v_analog/multicast.html --/ɛvɪs/ /tɑːk/ /kɑntɹɪbjuʃ(ə)nz/ 21:52, July 13, 2005 (UTC)

(2.5) analogue switchoff

I've attempted to reword the "In general, viewers who are happy with their existing analog TV systems tend not to adopt terrestrial DTV systems (so-called "digital refuseniks")" section a bit. Some of us supposed "refuseniks" are actually existing DVB-S dish users who are refusing to buy a *second* digital settop box for each TV just to receive local programming.

Alas, the section is still US-centric and could still use some work. --carlb 23:18, 7 August 2005 (UTC)

OTA?

Say what OTA means. Over the air?

OTA, FTA, broadcast TV, terrestrial TV, off-the-air reception, etc. - doesn't matter what you call it. Basically, broadcast TV is TV that you can pick up with a VHF/UHF antenna (aka "rabbit ears"), not with pay-TV services (aka MMDS, cable, satellite, etc.); thus the service is free (apart from the TV, the antenna, and the antenna tuner (in my house, we only pick up broadcast TV, and our tuner is the VCR)). The only downside with broadcast TV is that you are limited to whatever you can pick up in your vicinity, which in most cases will be local channels. In my case I can pick up channels from the Providence and Boston metro areas, since I live in Pawtucket, Rhode Island and Pawtucket is north of Providence yet we can pick up Boston channels (such as WHDH and WGBH) free and clear. However, what you can pick up on broadcast TV varies from country to country. In Ireland, for example, only RTE's two channels, TV3, and the Gaelic TV station TG4 can be picked up; in Sydney, Australia, however, ABN-2 (ABC Australia's Sydney station), 2EA (SBS's Sydney staion), ATN-7 (Sydney's Seven Network affiliate station), TCN-9 (the Nine Network's Sydney affiliate station), and TEN-10 (Network Ten's Sydney affiliate station) can be picked up on broadcast TV. Broadcast TV is being replaced by DTT (digital terrestrial television), which in the US and Canada's case is being replaced by ATSC. Hope this clears things up a bit. -Daniel Blanchette 19:27, 26 February 2006 (UTC)

Closed captioning

In U.S. only, closed captioning is a subtitle service for hearing impaired people. Huh? Closed captioning/subtitling is available on most digital TV (and many analogue TV) systems around the world. Is the captioning used in America in someway different to other captioning systems? smurrayinchester^{(User), (Talk)} 20:34, 7 May 2006 (UTC)

Yea, I'm afraid so. ATSC is incoporating some legacy standards such as the analogue closed-captioning standard instead of more modern ones like DVB Subtitles. -Daniel Blanchette 17:07, 12 July 2006 (UTC)

Merging digital terrestrial television page into digital television page?

Apparently someone (specifically, 121a0012 on 3 April 2006) has suggested the above headlined action and directed discussion of this idea to this page. This does not seem like a good idea to me. It would seem to me that television systems that use wireless (i.e., not cabled to the consumer) terrestrial (i.e., earth-mounted) transmission (which is my understanding of what digital terrestrial television is about) are a sufficiently large application domain to warrant their own page that is distinct from television over cable, satellite, etc. —SudoMonas 05:14, 1 July 2006 (UTC)

That's a reasonable argument, although not one I find particularly convincing. Right now most of the content of this article is about digital broadcast systems—there's very little material on digital cable and satellite systems. 121a0012 15:05, 1 July 2006 (UTC)

See my comments above on Clarification. Basically I agree that the Digital Television article should link to terrestrial, satellite, cable and mobile articles rather than merge them. --Alistair9210 08:50, 4 July 2006 (UTC)

I am against the merge of two articles. One is about the DTV format and the other is about the broadcasting channel. I think they are different things Commando happy!® 02:52, 11 July 2006 (UTC)

I am also against merging DTT with the main digital television page. You don't see people merging the digital cable page with the digital television page, so why merge DTT with digital television? Makes no sense to me. -Daniel Blanchette 17:03, 12 July 2006 (UTC)

It would seem peculiar to me to merge DTT with digital television. These seem to be quite distinct concepts. DTT is a particular specialisation which I feel merits it's own page. --Neilajh 17:31, 27 July 2006 (UTC)

Signal strength

Why are DTV stations broadcasting at such a low power level compared to their analog counterparts? For example, CFTO-TV Toronto is transmitting with only 17.4 kilowatts on Channel 40, while their Channel 9 transmitter is transmitting at 316 kilowatts, typical for VHF hi-band stations (allowed up to 325 kw)! Will the signal be boosted before the end of the transitional period to a more typical UHF signal of 5000 kilowatts? GBC 18:09, 20 July 2006 (UTC)

It's not a "low power level". The amount of power in an analogue television signal varies greatly over very short periods of time; analogue stations are regulated according to the peak power output (which happens during vertical sync pulses IIRC). Digital television signals do not vary in this way and are regulated on the basis of average power. For NTSC-M versus ATSC, a rough equivalence is 1 kW digital = 5 kW analogue. This is reflected in the power limits for digital stations; a full-power UHF DTV in the U.S. or Canada operates at 1 MW as opposed to 5 MW for analogue. There's also some processing gain in ATSC to take into consideration.

As for your specific example, Canada is several years behind the U.S. in the digital transition and so far as I know has not yet required stations to "maximize" their signals to the power level specified in their allotments in order to receive protection from future interference as the FCC has. For a station like CFTO, there is no economic sense in building a full-power facility on channel 40 when their eventual destiny is full-power on channel 9 (a much less expensive proposition). In addition, because Canada was late to the game and most stations are very close to the U.S. border, fewer full-power allotments are possible during the transition period. There's a channel 40 across the lake in Rochester which may prevent CFTO from operating at any higher power. 121a0012 02:35, 21 July 2006 (UTC)

Well, here's an added complication to the whole thing. Here in Pawtucket, Rhode Island, where I'm from, we receive channels both from Boston and Providence. This means we can pick up WGBH-TV, WBZ-TV, WCVB-TV, WHDH-TV, WFXT-TV, WSBK-TV, and WGBX-TV, among other stations, alongside the traditional WLNE-TV, WJAR-TV, WPRI-TV, and WNAC-TV, as well as Rhode Island PBS. However, the template lists only RI and CT stations (I'll fix that later). Anyway, these channels have degrees of varying power - i.e., ch44 (WGBX-TV) comes in very strong, even with occasional "ghosting" and loss of color in the signal; whilst ch4 (WBZ-TV) and the two Spanish TV stations Univision and Telefutura come in weak. Obviously, most of the Providence TV stations come in good, but ch6 (WLNE) doesn't come in good. If this is the situation in traditional terrestrial television here in my neck of the woods, L-rd only knows what the situation would be for digital TV. -Daniel Blanchette 15:47, 21 July 2006 (UTC)

Well, it doesn't really belong here, but since I happen to live in this market and some (not I) consider me an expert, that's not a hard question to answer. There has always been substantial overlap between the Providence and Boston stations; indeed, when the original VHF allotments were set out for southern New England, you had channel 6 in New Haven, channel 11 in Providence, channels 2, 4, and 7 in Boston, and channel 5 in Worcester. Very early on, the FCC realized that it had made a big mistake in assigning channels in the northeast and mid-Atlantic states, and about half of the stations were required to change channels to meet new spacing requirements. Channel 4 in Schenectady was much too close to channel 4 in New York, so it was moved to channel 6. This then forced New Haven to channel 8, but then made it possible to add the 6 in New Bedford. Providence's channel 11, then on Neuticoncanut Hill in Johnston, was also too close to New York, and moved to channel 10 from a new tower in Rehoboth, allowing Providence a third VHF station on channel 12. (This also made it possible to add channel 11 in Durham, N.H.) Worcester's channel 5 moved to Boston as a separate thing (and I forget whether this was before or after the original channel 2 failed to get off the ground).

Anyway, the result is that the because channel 6 is licensed to New Bedford, its transmitter cannot be located off Pine St. Rehoboth with the other Providence commercial stations. Digital TV stations in the U.S. are not required to cover their communities of license, so channel 6's digital service on channel 49 is located in Rehoboth (I believe it's on the 10 tower). This also allows channel 48 in Worcester to move its DTV into Boston.

Most of the Boston stations are within 40 miles of you so it's no surprise that you pick them up well as this is well within the grade-B contour of the signals. 2, 4, 5, 44, their DTVs, and 38's DT all transmit from the CBS tower in Needham; 25/31, 38, and 56/41 transmit from the UHF Candelabra about a mile away; and 7/42 has its own tower not far from there in Newton. The Boston-market stations you don't receive very well are mostly in different directions and farther away. Two stations, 62 and 68, transmit from downtown (but their DTVs are or will be in Newton). 66/23 has a tall tower on Parmenter Road in Hudson. Channel 27 is in Boylston, but it's mounted atop the tallest tower in Massachusetts.

Channel 4 is not as weak as you think. However, all of the VHF-low-band channels are very vulnerable to interference from a variety of man-made sources like car ignition systems and computers. This is why most stations which have the choice will be moving off that band; with ATSC even UHF is preferable. So 4 will move permanently to 30 in 2009, and likewise 2 to 19 and 5 to 20—but 7 will stay on 7 (dropping 42). In Providence, 12 moves to 13 and 64 moves to 12; unusually, 10 will keep its transitional channel 51 allotment.

The actual market designations no longer depend on the over-the-air signal but rather on viewing patterns and other demographic data. The Boston stations are not in the Providence market, and vice versa; it would in most cases not be appropriate to add Boston stations to the Providence market template.

</infodump> 121a0012 03:29, 22 July 2006 (UTC)

USA switch-off

"In the United States, all U.S. television broadcasts will be exclusively digital as of February 17, 2009, by order of the Federal Communications Commission." Technically, all analog TV operations in the U.S. must cease as of 11:59:59 pm on February 17, 2009, so all U.S. television broadcasts will be exclusively digital as of February 18, 2009.Terminalwally 14:03, 24 August 2007 (UTC)

"After the the switch-off the FCC will then auction off the unused (Analog) portion of the spectrum for additional channels or other communications traffic."

This isn't quite true. Currently the US has channels 2-83. A portion of this band (channels 52-69) are a part (or adjacent) to the 700 MHz band and that's what's going to be auctioned. New DTV channels can be placed in the existing VHF channels or the UHF channels 14-51. For interest, channels 84-99 were removed to clear the 900 MHz band for cellular and 800 MHz (channels 69-83) is also used for public safety and cellular. Dsm 01:01, 8 May 2007 (UTC)

I updated the language you pointed out. Note that 84–99 were never broadcast channels (those would be cable); it was 70–83 that were removed in the 1970s to clear the 800 MHz band for cellular service. Since the late 1990s the FCC has been creating incentives for broadcasters to clear off channels above 52, chunks of 60–69 were given to public safety. The analog shutdown will be the deadline for broadcasting above 700 MHz. —RandallJones 21:06, 9 May 2007 (UTC)

If people buy a digital TV receiver now, but not all TV stations in their area are telecasting digital yet, are they able to pick up the analog transmissions on those digital sets? I know that analog sets cannot receive digital signals. I'm just thinking of viewers who may not upgrade if they'll lose non-digital broadcasters until those companies upgrade, and I'm also thinking of people who take a digital set into an analog only area after analog shutdown (2009 in the US, 2011 in Canada) in major centres, or cannot buy an analog set to use in an analog-only community. (Canada will allow analog to continue in remote communities, mainly because of the cost of upgrade and the uneconomic nature of operating in remote communities.) GBC 00:25, 17 July 2007 (UTC)

I have yet to see a TV offered for sale with an ATSC tuner that does not also have an NTSC-M tuner. 121a0012 03:18, 17 July 2007 (UTC)

map

File:Television Digital.png

This Spanish map which might be useful here. Perhaps it can be translated --Astrokey44 13:53, 26 May 2007 (UTC)

Misleading

"Newer televisions are often capable of receiving an HD resolution of 1920 × 1080 in progressive scan (1080p), but broadcasters in most countries currently do not have the bandwidth to transmit these signals over the air."

I'm removing the above statement because two things in it are misleading. 1) Every American digital television is able to receive 1080p (up to 30fps) because it's part of the ATSC standard. It's up to the tuner to convert the signal to suit the display tech. 2) In a digital broadcasting system bandwidth is independent of resolution and frame rate. For example, broadcasting a film in 1080p would actually require less bandwidth for a given image quality than broadcasting it in 1080i.

I'm also removing "In the age of pay-TV" from "In the age of pay-TV, other ways have been devised to receive digital television." because pay-TV can be received terrestrially (in Finland over DVB-T + Conax CAM for example).

Totsugeki 07:55, 29 July 2007 (UTC)

Agreed, but the 1080p text was making a useful point, but it was obscured. How do you like my edit? ... richi 12:41, 29 July 2007 (UTC)

Who invented digital television?

Well, article is just saying that digital television was introduced in 1990's. In my opinion it should also have information who invented it and when and there should also be a history section... Tarmo Tanilsoo 04:30, 18 September 2007 (UTC)

Channel Allocation

Will this affect channels already on the air? WAVY 10 19:26, 24 September 2007 (UTC)

All U.S. channels already have been assigned two channels each. For example, channel 2 might be assigned "2" for analog and "25" for digital. On the day when analog broadcasting stops, "2" switches over to digital and "25" disappears completely. That way Channel 2 is still channel 2 on the dial. - Theaveng 19:42, 26 September 2007 (UTC)

Where'd you get this information from? I don't see the stations switching back to thier analog VHF channel's for thier digital signal as they can already make thier digital channel appear as thier original channel. You're more likely to see channel "2" stay on channel "25" but appear as channel 2 on your box. 71.114.48.205 (talk) 00:49, 25 June 2008 (UTC)

What RF channel U.S. stations will use after February 17 is determined by a combination of technical requirements and economics. For some stations, their final post-transition channel will be different from both their transitional digital channel and their historic analog channel. For example, I was just up in Vermont visiting WCAX-TV over the weekend; they currently have analog on channel 3 and digital on channel 53. 53 is "out of core", so they will not be permitted to keep it, but VHF-low channels are highly undesirable due to the level of natural and man-made interference and the low power limits in that band, so WCAX has been given permission to move to channel 22 when WVNY vacates it. WVNY, in turn, was assigned transitional digital channel 13, which they will keep, since the VHF-high band does not suffer from the same sort of interference, and VHF stations have dramatically lower power bills. Elsewhere in that market, WPTZ moves from 5 to 14, WCFE-TV moves from 57 to 38, WFFF-TV moves from 44 to 43, and WETK moves from 33 to 32—all of those stations are keeping their transitional digital channels permanently. WCWF came on the air too late to receive a transitional digital channel, so it will "flash cut" from analog to digital on channel 40. 121a0012 (talk) 04:13, 26 June 2008 (UTC)

Swedish switch-off

There has been some confusion about the switch-off of the Swedish analogue network, which has caused a small edit war. The SVT2 and TV4 transmitters were shut down on October 15, but most transmitters still carry SVT1 until October 29. This is however something which is often left out by the media, but it is mentioned in this press release from Teracom:

"SVT 1 fortsätter att sända analogt till och med 29 oktober från de större sändarstationerna Karlshamn, Karlskrona/Vämö, Malmö/Jägersro och Helsingborg/Olympia."

This translates as "SVT1 will continue its analogue broadcasts until October 29 from the Karlshamn, Karlskrona/Vämö, Malmö/Jägersro and Helsingborg/Olympia transmitters". Therefore, the final switch-off date of the Swedish analogue broadcasts is October 29, not October 15 which is often incorrectly stated. Väsk 19:40, 18 October 2007 (UTC)

Major reformatting, and I demoted USA from leading the article

Why is the USA mentioned at the top, and then again further down the article? Really the USA should take its proper place (at the bottom) in the article and leave the main heading clear and concise.

Bulleted lists are okay when the subject matter is short and to the point, but several items in these bullet lists are definitely not short and to the point, such as for Canada and especially the United States section. I've converted the bullets into proper subheadings, so that paragraph breaks can be used, which makes the article easier to read. (Probably should de-bullet other country lists as well.)

I've majorly expanded on the USA coupon assistence section, and from reading the Federal Register I see it has a bunch of specific limitations and qualifications that should be mentioned which I've also added (no DVI, no HDMI, etc). The two trailing bulleted qualifications also come from the Federal Register but I don't know how to re-refrence a dynamic citation that I've used earlier in an article. (Both bullets should cite the same source.)

The section on converter boxes is also not exclusive to the USA and I've split it off as a "disadvantage" to conversion. It is fairly certain that other countries will go through the same process of using converters for older devices. No country is going to have everyone run out and immediately purchase all-new television equipment.

And I've expanded disadvantages section with headings for each one. It's odd, I see a lot more disadvantages listed than advantages.. heh.

DMahalko (talk) 10:02, 14 December 2007 (UTC)

Effects of poor reception

This paragraph is very misleading, especially regarding NTSC/ATSC analog vs. digital. NTSC and ATSC are very different broadcasting schemes, so you can't just compare reception of NTSC with what you think ATSC would be like and assume it will work the same way. ATSC, unlike NTSC, can still provide a good picture with multipath or other echo distortion, and it is much more immune to electrical spark or lightning interference. Furthermore, ATSC needs less bandwidth and signal strength to get a usable image than NTSC does. So I think this article still needs some work. 4.242.108.88 (talk) 16:43, 2 January 2008 (UTC)

While I've not done any direct comparisons yet, I have found that the Dish Network Dish 500 HDTV/ASTC receiver usually craps out when the reception strength drops to 80% or less, which requires a huge eight foot roof-mounted VHF/UHF anntenna and dual-booster to be perfectly aligned on the station transmitter 40 miles away. Turn the antenna slightly to the side and the picture breaks up, the colors go wild, and it freeze-frames and dies, while the analog channels continue to be acceptable though with ghosting or static.

If a reliable scientific comparison of reception quality of NTSC vs ATSC on the same antenna and booster system is going to be done, there's only a year left to do it and counting. I doubt the DTV people are going to fund this study. :-) DMahalko (talk) 13:57, 3 January 2008 (UTC)

You just described the Cliff effect ... richi (talk) 12:21, 4 January 2008 (UTC)

I just described the fact that in real-world use, the claims about how good DTV reception is vs old analong are false. The fact is that the old technology of analog receivers is extremely good at picking out even the worst snowy and distorted sync signals to give a usable image, and DTV is going to make many fringe-reception stations unwatchable without a huge tower-mounted, rotating, multi-boosted antenna system to compensate for the failings of DTV's cliff effect. It's not so much of a cliff but a very small signal strength plateau above which the signal is viewable. DMahalko (talk) 17:05, 4 January 2008 (UTC)

Don't forget you're only describing the 8VSB transmission standard, as used in the US. In most other countries, DVB-T uses a much more robust method, COFDM, which is less suscepible to multipath problems, even at low field strengths. Alo, the "plateau" you describe is precisely the digital cliff effect ... richi (talk) 22:49, 4 January 2008 (UTC)

I have to completely agree with user DMahalko. Channels that I had no problem receiving their analog signal would break up to the point of being unwatchable in digital. Whereas I could acceptably receive 9 or 10 channels in analog, I could only get 1 watchable digital channel. I got rid of my TV not long after the conversion to all digital. --71.214.210.147 (talk) 19:47, 7 September 2012 (UTC)

The paragraph is misleading 'cause digital signals are extremely hard to pick up, bad weather or not! Someone needs to mention that an outside antenna is almost a requirement with the digital signal. Even one wall can completely cut off the signal, whereas with an analog signal it is pretty easy to get even if the antenna is in the middle of the house. I've heard it's because plumbing and wiring reflects the signal or something, but I don't know. All I know is it needs to be mentioned so people will know 'cause no news organization is doing it. —Preceding unsigned comment added by 24.31.114.93 (talk) 02:56, 19 May 2008 (UTC)

I live in a fringe area of Joplin, Missouri, and the simple truth is that digital/ATSC has turned out to be a mess. In this area there are four stations that broadcast in both analog/NTSC and digital/ATSC, plus a fifth that is analog only for now. Of the five analog channels, all are watchable, some better than others - one is easily as good as cable. Of the four digital broadcasts, two are constantly breaking down, turning to garbage, etc. and are generally not too pleasant to watch. One channel simply doesn't come in at all (no reception). The fourth one generally works fine. All of this on an antenna I built expressly to maximize my signal reception. A friend of mine with only a pair of rabbit ears has a similar situation, and she lives less than two miles from any of the transmitters in the area. Of the four digital transmissions, she can receive two of them and neither is watchable. So, I get one out of four, she gets ZERO out of four. To add insult to injury, one of the digital channels takes standard definition video, pillarboxes it, upscales it, and then broadcasts the result in high definition. If they're broadcasting a wide-screen film, they first letterbox the film as if it were destined for analog TV, then they pillarbox the result to 16:9, upscale it, and broadcast in high definition. The result is a tiny image a third of the size of my screen, surrounded by four thick black borders (a so-called windowbox). Unless the TV stations start turning the digital transmitter power up and fixing their mistakes, digital TV is going to have major usability problems in the USA. Vanessaezekowitz (talk) 16:59, 3 July 2008 (UTC)

I don't agree that the use of an outdoor directional antenna amounts to a "cure" of the given reception problems. First, the antenna may have to be *highly* directional in order to discriminate against reflections or echos from low observable angles from the signal source; in practice, using a directional antenna may likely not cure the multi-path problems, but only reduce them. Second, the use of a directional antenna means that an antenna would have to be physically pointed in different directions to pick up signals from sources at very different angles from each other (unless you have something amounting to a phased array antenna). Last, outdoor mounting of an antenna means that the antenna will be subject to wind effects, where wind caused displacement in the antenna amounting to less than 1 mm (peak-to-peak) has been seen to result in a complete loss of picture for 8VSB modulation of ATSC, as used in the USA. It is certainly clear that the claims of the superiority of DTV over analog television (as proselytized by every public service DTV transition announcement that I have seen on every channel) are overblown and completely ignore the difference in robustness of the old analog NTSC format compared with the new 8VSB-ATSC digital format. 140.142.183.42 (talk) 03:49, 7 January 2009 (UTC) Seattle-area analog and digital TV viewer.

Audio-only DTV radio reception?

I just thought of one possibly major problem with this conversion. Analog TV broadcast audio can be received by a cheap $15 TV-Radio that has TV channels on the tuning bands, and the FM audio played over the radio. Is anything this simple going to be possible when DTV takes hold?

I am under the impression that the audio is now going to be fully interwoven into the digital broadcast stream, and some heavy-duty broadcast reception, decompression, and processing is going to be necessary to just pull out the audio only. A portable DTV-Radio could well end up costing $150 or more just for the basic battery-powered DTV-decoder. DMahalko (talk) 03:27, 3 January 2008 (UTC)

I just bought a $50 DTV receiver for my analog set - that is more then is needed for audio. It says it uses 8 watts of power, so I don't think a battery powered DTV is out of the question. I tried using a paperclip as the antenna, and most of the stations came in clearly. However I have read that you can't receive ATSC from a MOVING antenna, (such as a car) so some other form of DTV is planned for mobile devices. Algr (talk) 20:41, 22 March 2008 (UTC)

Merging of duplicate material

I propose to clean up some of the information on this page (principally, analog switch-off) which is duplicated elsewhere.

Please see Talk:Technology_of_television#Proposed_Changes which I am going to implement shortly if no-one speaks up. IanHarvey (talk) 12:43, 20 February 2008 (UTC)

DIGITAL COAXIAL DAYS ON THE INTERNET:... these are days when you 'relay' the drivers for the sound card & the graphics card, and therefore reset priority;;; like when you used to budge the wire on the television,,,, and yet it is this day... —Preceding unsigned comment added by 86.139.112.177 (talk) 21:11, 22 February 2008 (UTC)

DTV Fringe Reception

I believe [Vanessaezekowitz's] recent change to the digital television oversimplified the reception issue a bit too much. It now reads as if "fringe" reception with analog is always superior, while the previous text at least made it clear that there can be situations where analog signal is unwatchable yet the digital signal comes in clearly. Rcooley (talk) 13:37, 16 April 2008 (UTC)

This probably sounds like original research, but my direct experience agrees with the general concensus that low-quality "fringe" reception results in a worse picture with ATSC, if you get one at all, than what you get from a traditional analog signal. However, I'll adjust the article a bit to reduce the "certainty" of the language.Vanessaezekowitz (talk) 16:59, 16 April 2008 (UTC)

Not only is it "original research", it is entirely anecdotal and unscientific. The equipment you happen to have is not necessarily representative of all the ATSC receiving equipment available. Local issues could also be far more significant than any inherent differences between analog and ATSC modulation/receivers. Most importantly, it is a completely unfair comparison. The ATSC transmitters are not identical to their analog counterparts by any stretch of the imagination. The vast majority of the time, the analog stations are lower frequency (VHF), broadcasting at very high power (relatively so, given the freq.), and often located in different physical locations. While the ATSC stations are much higher frequency (UHF), and broadcasting at relatively much lower power. The problems you have with reception MAY be entirely due to these issues, rather than any difference between analog and ATSC. Since you can't possibly know, it's not a factual statement fit for inclusion in an encyclopedia. And it doesn't make a good bit of "advice" either, as we are less than a year away from the full digital switchover, when the main transmitters will be switched over to digital, and these issues may well all be moot. Furthermore, I can certainly cite stories of similar anecdotal experiences where precisely the opposite result was true... ie. analog signal were so weak as to be unintelligible yet ATSC reception was perfect. And finally, it's a completely inaccurate description of the "digital cliff" effect, and that term should absolutely not be used. Rcooley (talk) 02:25, 17 April 2008 (UTC)

Ok, fair enough, but see above. If I am sitting there watching a regular, ordinary television set that receives digital/ATSC signals, and I can see it go from perfect to slightly garbled to total garbage to no picture at all, then that means the so-called digital cliff effect is either improperly defined or does not apply here (I did not add that reference, someone else did and I chose to keep it). The page as it reads now keeps the correct definition of digital cliff according to that term's page, and keeps the fact that some devices are less susceptible to the effect. —Preceding unsigned comment added by Vanessaezekowitz (talk • contribs) 17:21, 3 July 2008 (UTC)

Analog shutoff date change in the US

Twice on January 26, 2009 and once on January 27, edits have been made in the article to change the analog shutoff date in the United States from February 17, 2009 to June 12, 2009. These edits have apparently been based on the US Senate's recent passage of a bill changing the date. I have reverted the edits twice, citing them as premature because, in the US, a bill passed in the Senate is not yet a law. It must also be passed by the House of Representatives and signed by the President before it becomes law. Although the date change may happen eventually, please do not change the date in the article yet. --Thomprod (talk) 17:08, 27 January 2009 (UTC)

Ok, looks like it failed in the house. I'm going to edit out mention of it passing in the senate since that's now irrelevant. --Watchreader (talk) 19:14, 28 January 2009 (UTC)

I disagree. I think it should be included as relevant information to Digital television. Tiefoon (talk) 18:42, 29 January 2009 (UTC)

Maybe to US DTV but it really has nothing to do with DTV as the article stands. 06:32, 31 January 2009 (UTC)06:32, 31 January 2009 (UTC)~~ —Preceding unsigned comment added by 68.102.180.134 (talk)

Several times over the last few days, edits have been made reverting the analog shutoff date in the US back to February 17, 2009. The editors making these edits point out the older Public Service Announcements that set the original date of February 17, 2009 as the reason for their reverts. However, since those PSAs were produced and broadcast, the US Congress passed the DTV Delay Act which was signed into law by President Obama on February 11, 2009, as the article's first reference states. The date of June 12, 2009 is now correct (as of today) and will probably not be changed again. --Thomprod (talk) 10:53, 24 April 2009 (UTC)

New Channel allocations- need a table showing frequencies and numbers designation

How about including a table/chart showing the new channel number designations and frequency bands? --74.243.7.117 (talk) 16:28, 6 February 2009 (UTC)

In which countries? (Speaking for the U.S. only, there are no "new channel number designations and frequency bands", so presumably you are referring to some other country. Dumping a table of all 1,400 U.S. TV stations and their post-transition channel assignments would be pointless and a violation of WP:NOTDIR.) 121a0012 (talk) 03:25, 7 February 2009 (UTC)

A complete table of US station assignments is here: Tentative Digital Television (DTV) Channel assignment
The actual channel frequencies are listed here: Television Frequency Table
-71.174.175.84 (talk) 11:41, 17 June 2009 (UTC)

Image

The new image at the top seems kind of misleading. In my experience, if the analog picture looks that bad, then the digital picture will cut out all the time or may be out of range entirely.--SkiDragon (talk) 05:46, 15 April 2009 (UTC)

A comparison of a good analog image vs. a digital image will not show very much difference. The example is a bit extreme in that normally the digital image would long ago have disappeared entirely due to the cliff effect. The point, however, that was intended, was that analog images just get more and more grainy the weaker they get, but digital images remain exactly the same until they break up and then disappear. Feel free to write whatever caption seems appropriate. 2ndAmendment (talk) 06:10, 15 April 2009 (UTC)

Image was pointless with no caption. Even with caption, would probably be out of place in article intro. VMS Mosaic (talk) 08:28, 15 April 2009 (UTC)

Info on how to tape off of a set-top box?

I can't work it out, and I know there are a lot of other people who can't either. How do you set up your set-top box, your TV, and your DVD recorder/VCR so that you can tape programs? What connects to what? We're getting all these ads on TV at the moment (in Australia) telling us that the changeover is coming, but they don't provide the information we actually need. —Preceding unsigned comment added by 114.198.26.178 (talk) 14:03, 5 May 2009 (UTC)

I just added 3 external links at the bottom of the article to wikiHow articles that discuss how to do these things. Hope this is helpful. Waveguide2 (talk) 15:38, 11 June 2009 (UTC)

In order to tape programs "live", you just need to understand how to connect everything together properly... if you have a separate box. (If you have a new digital TV, most of them do not have video outputs, so recording on other equipment is impossible.) But the key thing to understand is that ordinary timed taping is not possible with the new equipment. Because you cannot program tuning-in to different channels at different times. The best you can do is leave the tuner box on, tuned to the channel you want to record, and set the timer on your recorder to record that signal at the proper time. Awkward. Sooner or later, it will force you to abandon your old VCR. Even if you get new VCR or DVD recording equipment, it will probably only record "standard" SD, not HD-quality. So you might as well just go all the way and get some device that records the full HD signal on a hard drive for later playback. Good luck finding a reliable one that does not require monthly subscription fees! -96.233.16.68 (talk) 11:51, 17 June 2009 (UTC)

"Barack Obama delayed the introduction of digital TV" not accurate

This is not quite accurate. First of all, it was a bill, then it was signed by the President. He didn't do it by himself. Secondly, it's not the INTRODUCTION of digital TV, it's the turnoff of analog TV that was pushed back. Hundreds of stations have been broadcasting in digital as an OPTION since the early 2000's. -Kb0ula (talk) 14:03, 12 June 2009 (UTC)

I removed Barack Obama, and the reference to "as part of an economic stimulus package" out in my edit. Congress passed the DTV Delay Act. If it was Obama's idea or part of a stimulus package, please feel free to add this back with citation. -- Skierpage (talk) 00:43, 14 June 2009 (UTC)

How is that an advantage?

A digital signal is rendered unwatchable with much less interference than an analog signal. This fact does not belong in the "Advantages to conversion" section. —Preceding unsigned comment added by 64.28.253.80 (talk) 19:24, 15 June 2009 (UTC)

Well, you are right -- but the problem was a bad section name. Renamed mis-named "Advantages to conversion" section to more encompassing "Conversion from analog to digital". -96.233.16.68 (talk) 12:12, 17 June 2009 (UTC)

Canada [13] | USA [5] | EBU [9, 12] | Japan & Brazil [36, 37]

What do mean those values ? [13], [5],[9. 12]...

--Mario CUSENZA (talk) 00:16, 25 February 2010 (UTC)

Wow....not many infos though....for the topic......

• http://scholar.google.com.hk/scholar?hl=en&q=allintitle%3A+television+urbanization&btnG=Search&as_sdt=2000&as_ylo=&as_vis=0

--222.64.212.26 (talk) 23:52, 12 May 2010 (UTC)

• http://scholar.google.com.hk/scholar?hl=en&q=allintitle%3A+tv+urbanization&btnG=Search&as_sdt=2000&as_ylo=&as_vis=0

--222.64.212.26 (talk) 23:55, 12 May 2010 (UTC)

Lead content.

The article states:

"...the glass in cathode ray tubes contains an average of 3.62 kilograms (8.0 lb) of lead."

This is sourced to an activist's statement that is not backed-up by an unbiased source. According to the How Stuff Works site, a large CRT contains about 5 lbs of lead. That is not sourced either but I don't think they have an axe to grind. Rsduhamel (talk) 20:04, 5 July 2011 (UTC)

Usage of Digital TV

Hello all, I think it could be useful to show some data on the usage of digital TV worldwide. This report holds some forecasts, such as how in 2017 the world will have approximately 1.3 billion digital TV households, with the penetration climbing from 48.6% in 2011 to 86.7% by 2017. We could include this information, what do you think? Here is the source: https://www.digitaltvresearch.com/ugc/DTV%20World%20HH%20TOC%20PDF_toc_50.pdf Cheers, Zalunardo8 (talk) 15:48, 10 January 2013 (UTC)

Broadcast XML Nominated for deletion - please help

As a standard used in Digital Television you should know that Broadcast Markup Language has been nominated for deletion by a user who is involved in trying to delete the BeerXML article and is now trawling Wikipedia for other articles to delete because they are losing that debate and feel that if other XML derived standards are deleted it might help them win the argument they are losing. Please challenge its deletion if you feel this is an unnacceptable. Regards Devils In Skirts! (talk) 12:53, 15 February 2014 (UTC)

Explain the expanded coverage with decreased power...

...as implied by pages like

• http://transition.fcc.gov/mb/engineering/dtvmaps/ and
• http://transition.fcc.gov/mb/engineering/maps/images/callsigns/WBPH.gif

The map is an image, so I can't C&P, so I'm retyping selected information.

The map (the .gif) is for WBPH-TV, analog channel 60, digital channel 9 located in Bethlehem, Pa.

It is apparently a map to show the change in coverage for terrestrial (iiuc (that is, OTA)) reception around the area. It says that the Digital License is (will have--was this a prediction?) 3.20 kW ERP at 284 m HAAT, while the analog is 2950 kW ERP at 286 m HAAT (I'm guessing that HAAT has something to do with the height of the transmitting antenna).

But:

  * the area bounded by the solid line (showing the area served by the digital transmission) is significantly bigger than the area bounded by the solid line (showing the area served by the analog transmission), and
  * concomittantly, at the bottom of the map, it indicates that the analog signal served (or had a potential audience of) 1,975,850 persons, while the digital signal serves (or was predicted to serve) (a potential audience of) 5,277,028 persons.
  

This seems almost magical.

Can anybody explain all (or, at least, some more) of the factors involved in what makes this change. I do see the one comment above that there is a difference in the method of power measurement for the analog vs. digital signal (the analog measured as the peak power, the digital measured as the average power), but several other stations that I looked at don't have anything close to a 1000 to 1 ratio between the two.

And, iiuc the 284 vs. 286 m HAAT, it seems like the increase in coverage occurs with a reduction in the height of the transmitting tower. (But my understanding of the HAAT acronym is strictly a guess.)

That's a general question, but I'd like to add some specific questions whose answers would be helpful or interesting to me:

• Is there some difference in the polarization of the signal between analog and digital that partially accounts for the difference in coverage? Or the behavior with respect to bouncing off the atmosphere (I wouldn't think so, only because the frequencies are in the same ballpark)?

• Does somebody here have a idea of how the actual consumption of electrical power has changed (if at all)?

• ???

I've looked at a few similar maps, all for the same general geographic area, and all that I looked at showed a considerable increase in coverage (i.e., potential audience) with the conversion to digital, and a considerable decrease in power (but most are not in the 1000 to 1 ration shown here--others seem to be more like 10 to 1).

It seems to me that there is something here that should be explained in an article on digital television or some related article.

Rhkramer (talk) 19:55, 8 June 2014 (UTC)

What the heck is going on in the 2nd sentence of this article??

There is some serious garbling mish mash in the second sentence at the very start of this article:

Digital TV is the (multicasting), that can Supports more than one channels in the same bandwidth regarding five times more pixels than conventional television

I can't parse what the heck happened to it so I'll leave it to someone else more qualified - but I just wanted to make people aware. It's really bad!

Wilsnipeforfood (talk) 12:38, 14 July 2014 (UTC)

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Mystery refs in table headings

There are some mysterious (to me) references in the table headings in Digital_television#Protection_parameters_for_terrestrial_DTV_broadcasting. This table was added in 2006 and the article had no references at this point so these numbers don't refer to our current reference list. Was this table inappropriately copied from another source? ~Kvng (talk) 20:03, 9 November 2021 (UTC)