We've all seen TV newscasts that show a reporter live in Iraq being interviewed by the CNN anchor back home in the ATL. There is always a few seconds delay since it takes time for the satellite signal to make it's way around the world.
OK, so I turn on my Nintendo Wii and I'm playing Mario Kart online with people from England, Brazil, China, Australia and Japan. I'm totally kicking ass as we all enjoy a fast-paced game of live racing action with no delay. How is this possible?
Is it because of the way the WWW is connected? Is it really hard- wired all the way around? I would think that the signal would have to hit a satellite at some point.
Annika1980 wrote: > We've all seen TV newscasts that show a reporter live in Iraq being > interviewed by the CNN anchor back home in the ATL. There is always a > few seconds delay since it takes time for the satellite signal to make > it's way around the world.
> OK, so I turn on my Nintendo Wii and I'm playing Mario Kart online > with people from England, Brazil, China, Australia and Japan. I'm > totally kicking ass as we all enjoy a fast-paced game of live racing > action with no delay. How is this possible?
> Is it because of the way the WWW is connected? Is it really hard- > wired all the way around?
Annika1980 wrote: > We've all seen TV newscasts that show a reporter live in Iraq being > interviewed by the CNN anchor back home in the ATL. There is always a > few seconds delay since it takes time for the satellite signal to make > it's way around the world.
> OK, so I turn on my Nintendo Wii and I'm playing Mario Kart online > with people from England, Brazil, China, Australia and Japan. I'm > totally kicking ass as we all enjoy a fast-paced game of live racing > action with no delay. How is this possible?
> Is it because of the way the WWW is connected? Is it really hard- > wired all the way around? I would think that the signal would have to > hit a satellite at some point.
Networks use satellite for portability reasons. They need a relatively small number of high bandwidth links that can run out of a truck from virtually anywhere.
The internet (backbone) uses land/submarine lines (esp. fibre optic) for international and national connection for reasons of extreme bandwidth, cost and low latency. Some microwave (tower to tower) for local / rural connection still at pretty high BW; and copper coax. Low latency is important for high speed networks.
There are huge fibre optic networks covering the world and if you google about you'll find maps of them. They carry the major bulk of the internet traffic.
There are some satellite based internet connections, eg: rural users who need higher bandwidth than the telephone provides. In these systems, typically the upload is over the phone (URL's don't need much BW) and the downlink is over satellite. Though for uploading a large file or e-mail it will take a while... the performance of these systems on the downlink side is often less than 1 Mbit/s.
(Vice cable modem service of up to 60 Mbit/s here; and over 100 Mbit/s fibre to the house service in some countries (S. Korea, Japan, Taiwan...)).
In article <2f191197-dcc6-4aa7-b027-4ca9419bf...@m38g2000yqd.googlegroups.com>,
Annika1980 <annika1...@aol.com> wrote: > We've all seen TV newscasts that show a reporter live in Iraq being > interviewed by the CNN anchor back home in the ATL. There is always a > few seconds delay since it takes time for the satellite signal to make > it's way around the world.
It is probably not propagation delay as much as time required for analog-to-digital and digital-to-analog conversion, perhaps at several points along the route. At least some of that delay is for error correction. And what you see is the total delay from the local anchor to the remote reporter and back again.
I've also noticed a difference in time between a standard FM radio broadcast and the same program on an HD radio channel.
Now if only they could get the sound to sync with the picture.
> In article > <2f191197-dcc6-4aa7-b027-4ca9419bf...@m38g2000yqd.googlegroups.com>, > Annika1980 <annika1...@aol.com> wrote:
>> We've all seen TV newscasts that show a reporter live in Iraq being >> interviewed by the CNN anchor back home in the ATL. There is always a >> few seconds delay since it takes time for the satellite signal to make >> it's way around the world.
> It is probably not propagation delay as much as time required for > analog-to-digital and digital-to-analog conversion, perhaps at several > points along the route.
Hmm; I'm no expert on this, but I don't see why in the world one would have D-A and A-D conversion on a signal that's in the digital domain and would be best handled by keeping it there.
> At least some of that delay is for error correction.
Now that makes sense, though I don't know how much ECD and ECC happens on such signals.
-- Who needs a junta or a dictatorship when you have a Congress blowing Wall Street, using the media as a condom?
Fred McKenzie wrote: > In article > <2f191197-dcc6-4aa7-b027-4ca9419bf...@m38g2000yqd.googlegroups.com>, > Annika1980 <annika1...@aol.com> wrote:
>> We've all seen TV newscasts that show a reporter live in Iraq being >> interviewed by the CNN anchor back home in the ATL. There is always a >> few seconds delay since it takes time for the satellite signal to make >> it's way around the world.
> It is probably not propagation delay as much as time required for > analog-to-digital and digital-to-analog conversion, perhaps at several
> In article > <2f191197-dcc6-4aa7-b027-4ca9419bf...@m38g2000yqd.googlegroups.com>, > Annika1980 <annika1...@aol.com> wrote:
>> We've all seen TV newscasts that show a reporter live in Iraq being >> interviewed by the CNN anchor back home in the ATL. There is always a >> few seconds delay since it takes time for the satellite signal to make >> it's way around the world.
> It is probably not propagation delay as much as time required for > analog-to-digital and digital-to-analog conversion, perhaps at several > points along the route. At least some of that delay is for error > correction. And what you see is the total delay from the local anchor > to the remote reporter and back again.
> I've also noticed a difference in time between a standard FM radio > broadcast and the same program on an HD radio channel.
> Now if only they could get the sound to sync with the picture.
Twaddle.
Analogue to digital conversion doesn't take significant time at all. In fact it takes place on a pixel by pixel basis so it's in the 10's to 100's of MHz region. There shouldn't be much going on anyway as even if the camera kit is analogue the intermediate systems won't be nor the final projection display.
Compression and error correction add a frame or two. The most I've ever seen used is 6 frames although some of the cheaper broadcasters might be pushing their luck further I guess. That's 120ms in UK speak, a little less in the US.
No, the bulk of any delay is the round trip to the satellite. Which tends only to be used when there's no other option.
<dwpa...@ist.uwaterloo.ca> wrote: >Annika1980 wrote: >> We've all seen TV newscasts that show a reporter live in Iraq being >> interviewed by the CNN anchor back home in the ATL. There is always a >> few seconds delay since it takes time for the satellite signal to make >> it's way around the world.
>> OK, so I turn on my Nintendo Wii and I'm playing Mario Kart online >> with people from England, Brazil, China, Australia and Japan. I'm >> totally kicking ass as we all enjoy a fast-paced game of live racing >> action with no delay. How is this possible?
>> Is it because of the way the WWW is connected? Is it really hard- >> wired all the way around?
Calvin Sambrook wrote: > "Fred McKenzie" <fm...@aol.com> wrote in message > news:fmmck-C24EB8.14005903112009@nntp.aioe.org... >> In article >> <2f191197-dcc6-4aa7-b027-4ca9419bf...@m38g2000yqd.googlegroups.com>, >> Annika1980 <annika1...@aol.com> wrote:
>>> We've all seen TV newscasts that show a reporter live in Iraq being >>> interviewed by the CNN anchor back home in the ATL. There is always a >>> few seconds delay since it takes time for the satellite signal to make >>> it's way around the world.
>> It is probably not propagation delay as much as time required for >> analog-to-digital and digital-to-analog conversion, perhaps at several >> points along the route. At least some of that delay is for error >> correction. And what you see is the total delay from the local anchor >> to the remote reporter and back again.
>> I've also noticed a difference in time between a standard FM radio >> broadcast and the same program on an HD radio channel.
>> Now if only they could get the sound to sync with the picture.
> Twaddle.
> Analogue to digital conversion doesn't take significant time at all. In > fact it takes place on a pixel by pixel basis so it's in the 10's to > 100's of MHz region. There shouldn't be much going on anyway as even if > the camera kit is analogue the intermediate systems won't be nor the > final projection display.
> Compression and error correction add a frame or two. The most I've ever > seen used is 6 frames although some of the cheaper broadcasters might be > pushing their luck further I guess. That's 120ms in UK speak, a little > less in the US.
> No, the bulk of any delay is the round trip to the satellite. Which > tends only to be used when there's no other option.
So, might Comcast be using Sat. as well- or what might they use to get the signal from Philly to SF Bay area? Microwave? - Kinda makes sense, as friend and I were watching the World Series 'together' in towns 20 miles apart, she on cable, and me on DirecTV, and her signal came in about two seconds later than mine. Sad to note that the picture was crumby. Said it was HD, but it was lo-Q HD at best. Probably 720i overly compressed.
> We've all seen TV newscasts that show a reporter live in Iraq being > interviewed by the CNN anchor back home in the ATL. There is always a > few seconds delay since it takes time for the satellite signal to make > it's way around the world.
> OK, so I turn on my Nintendo Wii and I'm playing Mario Kart online > with people from England, Brazil, China, Australia and Japan. I'm > totally kicking ass as we all enjoy a fast-paced game of live racing > action with no delay. How is this possible?
> Is it because of the way the WWW is connected? Is it really hard- > wired all the way around? I would think that the signal would have to > hit a satellite at some point.
I doubt if the delay is there because the satellite signal has to, "make its way around the world." At 186,000 miles per second, it gets around the world in .043 seconds. I rather suspect that the delay is due to other, ground based equipment, or perhaps even built-in political delays.
John McWilliams wrote: > So, might Comcast be using Sat. as well- or what might they use to get > the signal from Philly to SF Bay area? Microwave? - Kinda makes sense, > as friend and I were watching the World Series 'together' in towns 20 > miles apart, she on cable, and me on DirecTV, and her signal came in > about two seconds later than mine.
Television networks insert programming delays for their own reasons (coordination of commercials across the country, mainly, but occasionally for "bleep" operators on real time broadcasts like ball games).
Cable operators get some of their signal from local receivers and some from satellite.
> Sad to note that the picture was crumby. Said it was HD, but it was lo-Q > HD at best. Probably 720i overly compressed.
I haven't heard of television broadcasts above 720 to date.
>> So, might Comcast be using Sat. as well- or what might they use to get >> the signal from Philly to SF Bay area? Microwave? - Kinda makes sense, >> as friend and I were watching the World Series 'together' in towns 20 >> miles apart, she on cable, and me on DirecTV, and her signal came in >> about two seconds later than mine.
> Television networks insert programming delays for their own reasons > (coordination of commercials across the country, mainly, but > occasionally for "bleep" operators on real time broadcasts like ball > games).
> Cable operators get some of their signal from local receivers and some > from satellite.
>> Sad to note that the picture was crumby. Said it was HD, but it was >> lo-Q HD at best. Probably 720i overly compressed.
> I haven't heard of television broadcasts above 720 to date.
We regularly get programming in 1080 i, also 720 p; it's hard to tell the difference, esp. so as sources can be so variable. Some VOD is at 1080p, the top of the line so far for consumers in the US. (Blu-ray does this, and mileage varies according to the source and how well it's engineered on conversion from the Master.... or not Master, as the case often seems to be)
However, 720 i sucks badly, more so if the source is lacking or overcompressed.- as was my feed of the Baseball "World Series".
-- John McWilliams
When asked why he still lives in the UK despite working so much in the US, John Cleese had this to say: Number one, we speak English and you don't. Number two, when we hold a world championship for a particular sport, we invite teams from other countries. Number three, when one meets the Head of State in England, one has to go down on one knee only.
John McWilliams wrote: > Alan Browne wrote: >> John McWilliams wrote:
>>> So, might Comcast be using Sat. as well- or what might they use to >>> get the signal from Philly to SF Bay area? Microwave? - Kinda makes >>> sense, as friend and I were watching the World Series 'together' in >>> towns 20 miles apart, she on cable, and me on DirecTV, and her signal >>> came in about two seconds later than mine.
>> Television networks insert programming delays for their own reasons >> (coordination of commercials across the country, mainly, but >> occasionally for "bleep" operators on real time broadcasts like ball >> games).
>> Cable operators get some of their signal from local receivers and some >> from satellite.
>>> Sad to note that the picture was crumby. Said it was HD, but it was >>> lo-Q HD at best. Probably 720i overly compressed.
>> I haven't heard of television broadcasts above 720 to date.
> We regularly get programming in 1080 i, also 720 p; it's hard to tell > the difference, esp. so as sources can be so variable. Some VOD is at > 1080p, the top of the line so far for consumers in the US. (Blu-ray does > this, and mileage varies according to the source and how well it's > engineered on conversion from the Master.... or not Master, as the case > often seems to be)
> However, 720 i sucks badly, more so if the source is lacking or > overcompressed.- as was my feed of the Baseball "World Series".
Got it.
We don't have over the air digital mandates until 2011.08.31 though we do receive some US channels over the air (digital), cable (analog and digital). Some stations here do transmit their digital signal already since they feed that to the cable co's and sat services. I haven't bothered with the cable subscription for digital as I watch no more than 4 or 5 hours per week (2 hours is more usual) - including the usually excellent US PBS NOVA at 8 tonight (first of 3 parts on becoming human.
On Tue, 3 Nov 2009 14:24:14 -0800, "Bill Graham" <w...@comcast.net> wrote:
>"Annika1980" <annika1...@aol.com> wrote in message >news:2f191197-dcc6-4aa7-b027-4ca9419bf624@m38g2000yqd.googlegroups.com... >> We've all seen TV newscasts that show a reporter live in Iraq being >> interviewed by the CNN anchor back home in the ATL. There is always a >> few seconds delay since it takes time for the satellite signal to make >> it's way around the world.
>> OK, so I turn on my Nintendo Wii and I'm playing Mario Kart online >> with people from England, Brazil, China, Australia and Japan. I'm >> totally kicking ass as we all enjoy a fast-paced game of live racing >> action with no delay. How is this possible?
>> Is it because of the way the WWW is connected? Is it really hard- >> wired all the way around? I would think that the signal would have to >> hit a satellite at some point.
>I doubt if the delay is there because the satellite signal has to, "make its >way around the world." At 186,000 miles per second, it gets around the world >in .043 seconds. I rather suspect that the delay is due to other, ground >based equipment, or perhaps even built-in political delays.
There is definitely a delay in satellite TV, I know because I was once at a demonstration of satellite TV at McGill U. in Montreal, and I got to stand in front of a camera and wave, and watch myself on the monitor, waving back to myself a short time later!
Oh, your math is a bit screwy, the satellite is 24,000 miles up, so the full return trip is around 1/3 second, I guess...
And as for the Internet, there can easily be a 1/3 second delay between continents, since copper speed is a lot slower than light speed, and there are lots of "relay stations" providing propagation delay. I used to talk to people in Oz on Internet phone, and there was a bit of a delay in that.
When I worked in train dispatch, we had a problem with echo on the lines because the dispatchers are all in Toronto, and the radio towers are in Montreal. Thats only 320 miles and the delay was at least 100ms.
As for Annikas game server, there may be prop. delay compensation built in somehow... it only appears to him that there is no delay... it's best to ask the game operators!
It's funny, I sometimes watch TV on my computer, and if the regular TV is on, I can see a delay of over 1 second between them. If I miss a sentence, I get to hear it again a second later!
>We don't have over the air digital mandates until 2011.08.31 though we >do receive some US channels over the air (digital), cable (analog and >digital). Some stations here do transmit their digital signal already >since they feed that to the cable co's and sat services. I haven't >bothered with the cable subscription for digital as I watch no more than >4 or 5 hours per week (2 hours is more usual) - including the usually >excellent US PBS NOVA at 8 tonight (first of 3 parts on becoming human.
You're so right, Alan, TV here sucks big time! People ask me when I'm getting digital HD and I answer - "For what?"
On Tue, 03 Nov 2009 21:19:13 -0500, b...@nospam.com wrote: >It's funny, I sometimes watch TV on my computer, and if the regular TV is on, I >can see a delay of over 1 second between them. If I miss a sentence, I get to >hear it again a second later!
We are on Brighthouse cable. We have a cable convertor/recorder box in one room, and just cable connections to two other TVs. If I happen to have two TVs on, the direct cable connected TVs have a slight delay. Sometimes not more than one complete sentence of dialog. -- Tony Cooper - Orlando, Florida
>> all seen TV newscasts that show a reporter live in Iraq being >> interviewed by the CNN anchor back home in the ATL. There is always a >> few seconds delay since it takes time for the satellite signal to make >> it's way around the world.
>> OK, so I turn on my Nintendo Wii and I'm playing Mario Kart online >> with people from England, Brazil, China, Australia and Japan. I'm >> totally kicking ass as we all enjoy a fast-paced game of live racing >> action with no delay. How is this possible?
>> Is it because of the way the WWW is connected? Is it really hard- >> wired all the way around? I would think that the signal would have to >> hit a satellite at some point.
> I doubt if the delay is there because the satellite signal has to, > "make its way around the world." At 186,000 miles per second, it gets > around the world in .043 seconds. I rather suspect that the delay is > due to other, ground based equipment, or perhaps even built-in > political delays.
Actually, geostable satellites may be orbiting at 24000 miles up. That's 48000 miles up and back. So if I send my signal, you get it 48000 miles later. Then your signal does the same, up and back. That is nearly a half second delay, easily noticeable. -- Michael
Doug Payne wrote: > Annika1980 wrote: > > We've all seen TV newscasts that show a reporter live in Iraq being > > interviewed by the CNN anchor back home in the ATL. There is always a > > few seconds delay since it takes time for the satellite signal to make > > it's way around the world.
> > OK, so I turn on my Nintendo Wii and I'm playing Mario Kart online > > with people from England, Brazil, China, Australia and Japan. I'm > > totally kicking ass as we all enjoy a fast-paced game of live racing > > action with no delay. How is this possible?
> > Is it because of the way the WWW is connected? Is it really hard- > > wired all the way around?
Shortly after communication satellites were launched in geosync orbits the common carriers decided that quarter second delay was too much for pleasant conversation. This has meant that c common carriers and most internet data goes via fibre optic cable with delays in in the order of 47ms. Satellite phones still have the quarter second delay.
> "Annika1980" <annika1...@aol.com> wrote in message > news:2f191197-dcc6-4aa7-b027-4ca9419bf624@m38g2000yqd.googlegroups.com... >> We've all seen TV newscasts that show a reporter live in Iraq being >> interviewed by the CNN anchor back home in the ATL. There is always a >> few seconds delay since it takes time for the satellite signal to make >> it's way around the world.
>> OK, so I turn on my Nintendo Wii and I'm playing Mario Kart online >> with people from England, Brazil, China, Australia and Japan. I'm >> totally kicking ass as we all enjoy a fast-paced game of live racing >> action with no delay. How is this possible?
>> Is it because of the way the WWW is connected? Is it really hard- >> wired all the way around? I would think that the signal would have to >> hit a satellite at some point.
> I doubt if the delay is there because the satellite signal has to, "make > its way around the world." At 186,000 miles per second, it gets around the > world in .043 seconds. I rather suspect that the delay is due to other, > ground based equipment, or perhaps even built-in political delays.
Communications satelites are orbitting (IIRC) at about 22,000 miles above the equator. The signal has to go up and back down, so each satelite hop is 40,000 miles. To go around the world would requires a minimum of three hops, which would be about 120,000 miles, or about 2/3 second. There is a lot of signal processing equipment along the way, causing additional delay.
>> I rather suspect that the delay is due to other, ground based >> equipment, or perhaps even built-in political delays.
> "Political delay" like, oh, I don't know, *liberals* intentionally causing > delays so Obama can vet the content? Uh huh.
> You're *such* a fucking idiot, Graham.
I speak of political delays of the type that are involved with editing out bad language, or verifying clean signal quality, etc. Delays that are not simply caused by electronic necessity, but which are involved with human induced quality control.....It is idiotic to jump to conclusions without knowing anything about what is being discussed.
> On Tue, 3 Nov 2009 14:24:14 -0800, "Bill Graham" <w...@comcast.net> wrote:
>>"Annika1980" <annika1...@aol.com> wrote in message >>news:2f191197-dcc6-4aa7-b027-4ca9419bf624@m38g2000yqd.googlegroups.com... >>> We've all seen TV newscasts that show a reporter live in Iraq being >>> interviewed by the CNN anchor back home in the ATL. There is always a >>> few seconds delay since it takes time for the satellite signal to make >>> it's way around the world.
>>> OK, so I turn on my Nintendo Wii and I'm playing Mario Kart online >>> with people from England, Brazil, China, Australia and Japan. I'm >>> totally kicking ass as we all enjoy a fast-paced game of live racing >>> action with no delay. How is this possible?
>>> Is it because of the way the WWW is connected? Is it really hard- >>> wired all the way around? I would think that the signal would have to >>> hit a satellite at some point.
>>I doubt if the delay is there because the satellite signal has to, "make >>its >>way around the world." At 186,000 miles per second, it gets around the >>world >>in .043 seconds. I rather suspect that the delay is due to other, ground >>based equipment, or perhaps even built-in political delays.
> There is definitely a delay in satellite TV, I know because I was once at > a > demonstration of satellite TV at McGill U. in Montreal, and I got to stand > in > front of a camera and wave, and watch myself on the monitor, waving back > to > myself a short time later!
> Oh, your math is a bit screwy, the satellite is 24,000 miles up, so the > full > return trip is around 1/3 second, I guess...
> And as for the Internet, there can easily be a 1/3 second delay between > continents, since copper speed is a lot slower than light speed, and there > are > lots of "relay stations" providing propagation delay. I used to talk to > people > in Oz on Internet phone, and there was a bit of a delay in that.
> When I worked in train dispatch, we had a problem with echo on the lines > because > the dispatchers are all in Toronto, and the radio towers are in Montreal. > Thats > only 320 miles and the delay was at least 100ms.
> As for Annikas game server, there may be prop. delay compensation built in > somehow... it only appears to him that there is no delay... it's best to > ask the > game operators!
> It's funny, I sometimes watch TV on my computer, and if the regular TV is > on, I > can see a delay of over 1 second between them. If I miss a sentence, I get > to > hear it again a second later!
You are quite correct. There are delays other than the speed of the transmission. It takes time for relays to energize and signal levels to steady out in capacitive circuits. Also the "political" delays I spoke of above involved with verification of signal quality and/or content.
>>> all seen TV newscasts that show a reporter live in Iraq being >>> interviewed by the CNN anchor back home in the ATL. There is always a >>> few seconds delay since it takes time for the satellite signal to make >>> it's way around the world.
>>> OK, so I turn on my Nintendo Wii and I'm playing Mario Kart online >>> with people from England, Brazil, China, Australia and Japan. I'm >>> totally kicking ass as we all enjoy a fast-paced game of live racing >>> action with no delay. How is this possible?
>>> Is it because of the way the WWW is connected? Is it really hard- >>> wired all the way around? I would think that the signal would have to >>> hit a satellite at some point.
>> I doubt if the delay is there because the satellite signal has to, "make >> its way around the world." At 186,000 miles per second, it gets around >> the world in .043 seconds. I rather suspect that the delay is due to >> other, ground based equipment, or perhaps even built-in political delays.
> Actually, geostable satellites may be orbiting at 24000 miles up. That's > 48000 miles up and back. So if I send my signal, you get it 48000 miles > later. Then your signal does the same, up and back. That is nearly a half > second delay, easily noticeable. > -- > Michael
True, but I have noticed delays of over a second with overseas TV communications......I believe this is due to other factors than satellite distances.
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