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#32
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Satellite to Satellite communication ?
Thanks for setting me straight Francois, you are correct "(null)" wrote in message news:1070919774.530038@smirk... Stewart Smith wrote: "Paul F. Dietz" wrote in message ... Marc 182 wrote: Multi-jump communications would create unacceptable delay in a voice conversation due to the speed of light and the distance to the satellites. Even a single jump causes a noticeable and annoying delay. That's why trans-Atlantic/Pacific cables remain popular. Cables are popular because they're *cheaper* than satellites (per unit of delivered bandwidth) what with the incredible advances in fiber optics. Has anybody ever heard of Echo-Cancelling devices? These can mitigate the effect of the "bounce" to a great degree. Also, to compensate further, "Reverb" can be added to flesh out tone and timbre. Echo cancelling does nothing to reduce time-of-flight issues. A half-second delay is still a half-second delay. Adding reverb is contraindicated for telephone communications, as it tends to reduce intelligibility. Check out speakerphones for examples thereof. As a matter of fact, there is a fair bit of research for _reducing_ reverberation in speakerphones. Signal processing techniques are not useful for fixing problems due to speed of light causing delays. 300,000 km/second: not just a good idea, it's the law. Francois. --- Outgoing mail is certified Virus Free. Checked by AVG anti-virus system (http://www.grisoft.com). Version: 6.0.548 / Virus Database: 341 - Release Date: 12/5/03 |
#33
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Satellite to Satellite communication ?
Thanks for setting me straight Francois, you are correct "(null)" wrote in message news:1070919774.530038@smirk... Stewart Smith wrote: "Paul F. Dietz" wrote in message ... Marc 182 wrote: Multi-jump communications would create unacceptable delay in a voice conversation due to the speed of light and the distance to the satellites. Even a single jump causes a noticeable and annoying delay. That's why trans-Atlantic/Pacific cables remain popular. Cables are popular because they're *cheaper* than satellites (per unit of delivered bandwidth) what with the incredible advances in fiber optics. Has anybody ever heard of Echo-Cancelling devices? These can mitigate the effect of the "bounce" to a great degree. Also, to compensate further, "Reverb" can be added to flesh out tone and timbre. Echo cancelling does nothing to reduce time-of-flight issues. A half-second delay is still a half-second delay. Adding reverb is contraindicated for telephone communications, as it tends to reduce intelligibility. Check out speakerphones for examples thereof. As a matter of fact, there is a fair bit of research for _reducing_ reverberation in speakerphones. Signal processing techniques are not useful for fixing problems due to speed of light causing delays. 300,000 km/second: not just a good idea, it's the law. Francois. --- Outgoing mail is certified Virus Free. Checked by AVG anti-virus system (http://www.grisoft.com). Version: 6.0.548 / Virus Database: 341 - Release Date: 12/5/03 |
#34
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Satellite to Satellite communication ?
"Greg D. Moore (Strider)" wrote:
"Norris Watkins" wrote in message om... Hello: 1. When you make an international phone call - say from NY to China - how does the voice data travel ? Does it have to be send to the satellite and then received at teh ground, some distance away, then sent to another satellite till it reaches the destination country. ? I mean is there any direct satellite to satellite communication. Or is it always bouncing between teh satellite and the ground at an angle. Generally ground to sat to ground and that's it. Sat to sat communication is fairly rare. It's been my imprression that there may be some military sat-to-sat stuff going on at 60 gigahertz. This band is readily absorbed by oxygen, making ground intercept of these signals impractical. (Googling for a minute) Here's a reference: http://www.ydi.com/deployinfo/wp-benefits-60ghz.php -- You know what to remove, to reply.... |
#35
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Satellite to Satellite communication ?
"Greg D. Moore (Strider)" wrote:
"Norris Watkins" wrote in message om... Hello: 1. When you make an international phone call - say from NY to China - how does the voice data travel ? Does it have to be send to the satellite and then received at teh ground, some distance away, then sent to another satellite till it reaches the destination country. ? I mean is there any direct satellite to satellite communication. Or is it always bouncing between teh satellite and the ground at an angle. Generally ground to sat to ground and that's it. Sat to sat communication is fairly rare. It's been my imprression that there may be some military sat-to-sat stuff going on at 60 gigahertz. This band is readily absorbed by oxygen, making ground intercept of these signals impractical. (Googling for a minute) Here's a reference: http://www.ydi.com/deployinfo/wp-benefits-60ghz.php -- You know what to remove, to reply.... |
#36
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Satellite to Satellite communication ?
"Ken Taylor" writes:
Echo cancellation reduces echo, it doesn't do anything to delay except potentially add to it. Delay doesn't show up as an echo - echo is due to mismatches; delay is due to propagation delays, processing delays, and similar time-wasters. You need a thiotimoline injector to solve the delay issue. -- A host is a host from coast to & no one will talk to a host that's close........[v].(301) 56-LINUX Unless the host (that isn't close).........................pob 1433 is busy, hung or dead....................................20915-1433 |
#37
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Satellite to Satellite communication ?
"Ken Taylor" writes:
Echo cancellation reduces echo, it doesn't do anything to delay except potentially add to it. Delay doesn't show up as an echo - echo is due to mismatches; delay is due to propagation delays, processing delays, and similar time-wasters. You need a thiotimoline injector to solve the delay issue. -- A host is a host from coast to & no one will talk to a host that's close........[v].(301) 56-LINUX Unless the host (that isn't close).........................pob 1433 is busy, hung or dead....................................20915-1433 |
#38
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Satellite to Satellite communication ?
Paul F. Dietz wrote: Cables are popular because they're *cheaper* than satellites (per unit of delivered bandwidth) what with the incredible advances in fiber optics. Paul Perhaps for large metropolitan areas. I live in a little podunk place 120 miles from Tucson or Phoenix. Folks on the nearby rez who'd have no way of getting fiber optic or cable are getting dishes. However the metropolitan markets are much more lucrative. Don't know if reaching the planet's rural areas justifies comsats. -- Hop David http://clowder.net/hop/index.html |
#39
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Satellite to Satellite communication ?
Paul F. Dietz wrote: Cables are popular because they're *cheaper* than satellites (per unit of delivered bandwidth) what with the incredible advances in fiber optics. Paul Perhaps for large metropolitan areas. I live in a little podunk place 120 miles from Tucson or Phoenix. Folks on the nearby rez who'd have no way of getting fiber optic or cable are getting dishes. However the metropolitan markets are much more lucrative. Don't know if reaching the planet's rural areas justifies comsats. -- Hop David http://clowder.net/hop/index.html |
#40
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Satellite to Satellite communication ?
In article 1070919774.530038@smirk, says...
Echo cancelling does nothing to reduce time-of-flight issues. A half-second delay is still a half-second delay. A half second is a half second, but canceling the echo does help intelligibility by removing some noise from the signal. Time-of-flight isn't the only issue. Adding reverb is contraindicated for telephone communications, as it tends to reduce intelligibility. Check out speakerphones for examples thereof. Excessive reverb is a bad thing. Done correctly, reverb adds a sense of presence without interfering with intelligibility. Signal processing techniques are not useful for fixing problems due to speed of light causing delays. True, but these tools are useful for lots of other real-world problems. -- Kevin Willoughby lid Imagine that, a FROG ON-OFF switch, hardly the work for test pilots. -- Mike Collins |
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