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2007-07-05
, 14:47
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Posts: 269 |
Thanked: 4 times |
Joined on Feb 2007
@ Finland
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#12
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Originally Posted by JKolstad
confirmed by a chat I had with s-o inside Nokia about this subject in the N800
Actually, it's somewhat clever. This approach is called "diversity reception," and depending on how it's implemented, is something as simple as selecting the antenna that has the stronger signal strength to something called "maximum ratio combining" where the two signals are summed together in a special way (this is actually the precursor of MIMO systems). Diversity reception has been around for decades -- and is pretty much ubiquitous in all laptops today for WiFi. It significantly improves the average signal strength a device receives, particularly when the devices is in motion: Just walking around often creates short-term fading in one antenna that can easily reduce its output to 1/100 or even 1/1000 or the typical signal strength; having a second antenna that's in a different location gives you a very good chance that at least one of the antennas is still getting a decent signal.
---Joel
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2007-07-05
, 16:02
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Posts: 6 |
Thanked: 0 times |
Joined on Jul 2007
@ Finland
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#13
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Originally Posted by JKolstad
Oh yes, I'm aware of transmit/receive diversity and their advantages. And if in our case, N800, diversity is used, it would explain those two? antennas. But if the diversity is not used and we still have two antennas and BT/wifi uses only one of them, why there is two pieces? And what is the frequency of other one? Would be great if someone could calculate the frequency, I don't know what kind of effect the angle has, if it has.
Actually, it's somewhat clever. This approach is called "diversity reception," and depending on how it's implemented, is something as simple as selecting the antenna that has the stronger signal strength to something called "maximum ratio combining" where the two signals are summed together in a special way (this is actually the precursor of MIMO systems). Diversity reception has been around for decades -- and is pretty much ubiquitous in all laptops today for WiFi. It significantly improves the average signal strength a device receives, particularly when the devices is in motion: Just walking around often creates short-term fading in one antenna that can easily reduce its output to 1/100 or even 1/1000 or the typical signal strength; having a second antenna that's in a different location gives you a very good chance that at least one of the antennas is still getting a decent signal.
---Joel
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2007-07-05
, 16:05
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Posts: 6 |
Thanked: 0 times |
Joined on Jul 2007
@ Finland
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#14
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Originally Posted by Seb Per
So, There is a diversity combiner in N800?
confirmed by a chat I had with s-o inside Nokia about this subject in the N800
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2007-07-05
, 16:14
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Posts: 269 |
Thanked: 4 times |
Joined on Feb 2007
@ Finland
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#15
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Originally Posted by TheSkyIsFalling
Not sure. What I was told : "It is correct that there can be 2 antennas for the same "activity"* in our devices"
So, There is a diversity combiner in N800?
No comment at all on the fact that there is this 0,234 W emitter. Damn... However I was told by the same source before that the clue would be the output power.
* : I don't recall the exact term used. was it module?
Actually, it's somewhat clever. This approach is called "diversity reception," and depending on how it's implemented, is something as simple as selecting the antenna that has the stronger signal strength to something called "maximum ratio combining" where the two signals are summed together in a special way (this is actually the precursor of MIMO systems). Diversity reception has been around for decades -- and is pretty much ubiquitous in all laptops today for WiFi. It significantly improves the average signal strength a device receives, particularly when the devices is in motion: Just walking around often creates short-term fading in one antenna that can easily reduce its output to 1/100 or even 1/1000 or the typical signal strength; having a second antenna that's in a different location gives you a very good chance that at least one of the antennas is still getting a decent signal.
---Joel