I don't post here very often, but this time I couldn't handle this. (Maybe I should drink less coffee). There was probably some paper at that uni, talking about an incremental improvement in frequency divider design. Ok, cool... we may or may not see in in a PLL chip in a few years. But the news release (TFA) and RP's writeup are rubbish. Actually, after a bit of Googling, it's all over the net. Next thing I expect, my PHB will ask me to change my totaly unrelated design to use ILFD. My signature notwithstanding, I'll try to pick out some of the c***p, and put some actual information in. BTW, I design 3G mobile terminal circuitry full time. And yes, I am an arrogant SOB. That doesn't make me wrong.
"...But now, researchers of the University of Rochester have developed a wireless chip that needs ten times less power [GC] than current designs."
So far so good.
The new chip relies on a technology named injection locked frequency divider (ILFD) which dramatically reduces the time needed to check for transmission frequencies which are performed several billion times per second by your current phone.
This statement is wrong 2 times. First of all, the time needed to check for transmission frequencies depends on PLL settling time. Nothing to do with divider technology. Even broader scope, it is a rare occurence in 3G that the phone needs to change RF frequency. It's WCDMA, so all cells from a given operator transmit on the same channel. Secondly, tthe checking for transmission does NOT occur "several billion times per second". The RF carrier frequency is several billion cycles per second (ie several GHz). But the carrier frequency is changed on every 10ms roughly, even when it needs to happen. That's 100 times per second. GSM is different, as it does frequency hopping normally, but that doesn't change the point: nothing to do with divider technology.
The new chip uses five transistors and can perform divisions by 3 instead of only 2 by previous circuits
OK, agreed. Anyway, who gives a f**k. A modern PLL chip has a programmable divider, settable from 3 to several thousand. Yes, 3, because it is different technology.
..., allowing a perfect communication between two phones communicating at 2.0001 and 2.0002 gigahertz respectively.
That's not how mobile phones work. Mobiles establish connection with the cell (base station), then remain frequency locked to it, to compensate for temperature dependant frequency variation of their reference reference crystal oscillators - and Doppler shift, if they are moving. A "perfect" communication hardly ever depends on this. And frequency locking does not happen via changing PLL settings in this case anyway - too coarse steps, so other techniques are used.
Anyway, as other people posted already, the frequency synthesizer is not significant contributor to mobile terminal power consumption. Even old PLL chips only use a few milliamps
The ILFD technology seems to be good for building efficient frequency dividers at higher microwave frequencies. That will probably not affect current mobile phones anyway, because all the current systems work around 1-2GHz. Higher up, it's difficult to achieve coverage. Again, other people already pointed this out.
If you want real news in this area, go to sites like this, or this. Slashdot's editorial quality has degraded in the last few years so much that I am thinking about deleting it from my bookmarks.
First I thought how useless this is - Microsoft trying to modify Windows to sell a few dozen licences to run on dozens of different platforms (each supercomputer is custom-designed, no?). Also - the programs that run on these machines are just huge sets of calculations, and the operating system is irrelevant... you probably don't even need one...
But then I RTFM - they just setup Windows to simplify clustering. Linux has had that for long time. Nothing to see here, please move along.
Sorry, but they don't have the mentality to capture the subtle hilarity of the Hitchikers guide. It's like a industrial drill operator trying to do a brain microsurgery...
If developers can choose the language to use (often the case when developing 'scripts'), the people that select Perl or Python will almost always outperform people who choose Visual Basic.
Languages are not equal. Perl, Python, etc. are designed for hackers by hackers. Visual Basic, Java, etc. are comitee designed languages for the incompetent.
BTW, it's possible to fuck up in any language, if you try hard enough...
In my experience, it's much harder to develop DSP software compared to developing hardware for the same task. Hardware design these days is a mature engineering discipline. Software development remains a high-risk black art, DSP doubly so. Also, for some signal processing tasks, the demand on processing power far outstrips the current processors. For something like a 3G modem you might need 20 Gigaflops to implement it in software. Even a plain well designed comms receiver from 20 years ago with a couple of crystal filters cannot be fully emulated with today's DSP technology. Complemented and enhanced - yes, but not emulated. How do you show that software-defined radio is up to more than just filling a very limited and specialised niche?
This is just a different method of sharing spectrum among different users. The currently used methods are pretty good. They have been under development for about 100 years. The Rf spectrum is a limited resource. The amount of information that can be transmitted over the spectrum is limited by Shannon's theorem (read his 1949 paper). This limit can't be increased. What UWB does is spreading its information over really wide bandwidth, raising the noise floor for everybody else. If there are enough UWB transmitters around, they will interfere with each other to the point of uselessness. Also, this will f**k up every other user of the Rf spectrum. In addition, with UWB, the spectrum can't be managed by assigning different frequency bands to different entities. Everyone jsut uses all of the spectrum all the time. The strongest transmitter wins. Sounds like this technology has a good chance of being approved in the US...
while (in_space == 1)
{
if (Abs(speed_error)>threshold))
{
fire_thrusters(-speed_error);
msg_to_nasa("This is AI here. I have just corrected the speed! Send a news release.");
}
else
{
msg_to_nasa("This is AI here. Everything is OK.");
sleep(100);
};
};
msg_to_nasa("This is AI here. I have landed!");
... Since when do you call feedback "artificial intelligence"? Gimme a break NASA.
having no intelligence of it's own, it is no more a 'robot' than a bulldozer, controlled by a remote...
virtual reality? oh please, give me a break...
how to get publicity and funding: build a 1950s-sci-fi-style remote controlled mechanic toy in the shape of human body and call it a robot. then throw in a few passé catch-phrases like 'virtual reality' or 'fractal automata' or 'nano'-whatever...
1) The sticks on the picture look like VHF omnidirectional antennae. Also, you only need large antennae when the satellite is far away, like geostationary orbit. On the Low Earth Orbit (~800km), all that is needed is a very small transmitter, comparable to a mobile phone in terms of power; well, at least for low bandwidth connections. There are quite a few tiny satellites like that in orbit right now. They are being used radio hams , scientific experiments, etc...
Another part of the answer is that dishes can only reasonably be used at microwave frequencies (above 1GHz), otherwise they would be too large
2) With omnidirectional antennae, there is no need for attitude control, see above.
The fact that the system uses DSSS (direct sequence spread spectrum) should minimize the interference. I wonder if anyone has done any real testing on how many networks can operate at the same time.
Slashdot Mirror
I don't post here very often, but this time I couldn't handle this. (Maybe I should drink less coffee). There was probably some paper at that uni, talking about an incremental improvement in frequency divider design. Ok, cool ... we may or may not see in in a PLL chip in a few years. But the news release (TFA) and RP's writeup are rubbish. Actually, after a bit of Googling, it's all over the net. Next thing I expect, my PHB will ask me to change my totaly unrelated design to use ILFD. My signature notwithstanding, I'll try to pick out some of the c***p, and put some actual information in. BTW, I design 3G mobile terminal circuitry full time. And yes, I am an arrogant SOB. That doesn't make me wrong.
"...But now, researchers of the University of Rochester have developed a wireless chip that needs ten times less power [GC] than current designs."
So far so good.
The new chip relies on a technology named injection locked frequency divider (ILFD) which dramatically reduces the time needed to check for transmission frequencies which are performed several billion times per second by your current phone.
This statement is wrong 2 times. First of all, the time needed to check for transmission frequencies depends on PLL settling time. Nothing to do with divider technology. Even broader scope, it is a rare occurence in 3G that the phone needs to change RF frequency. It's WCDMA, so all cells from a given operator transmit on the same channel. Secondly, tthe checking for transmission does NOT occur "several billion times per second". The RF carrier frequency is several billion cycles per second (ie several GHz). But the carrier frequency is changed on every 10ms roughly, even when it needs to happen. That's 100 times per second. GSM is different, as it does frequency hopping normally, but that doesn't change the point: nothing to do with divider technology.
The new chip uses five transistors and can perform divisions by 3 instead of only 2 by previous circuits
OK, agreed. Anyway, who gives a f**k. A modern PLL chip has a programmable divider, settable from 3 to several thousand. Yes, 3, because it is different technology.
That's not how mobile phones work. Mobiles establish connection with the cell (base station), then remain frequency locked to it, to compensate for temperature dependant frequency variation of their reference reference crystal oscillators - and Doppler shift, if they are moving. A "perfect" communication hardly ever depends on this. And frequency locking does not happen via changing PLL settings in this case anyway - too coarse steps, so other techniques are used.
Anyway, as other people posted already, the frequency synthesizer is not significant contributor to mobile terminal power consumption. Even old PLL chips only use a few milliamps
The ILFD technology seems to be good for building efficient frequency dividers at higher microwave frequencies. That will probably not affect current mobile phones anyway, because all the current systems work around 1-2GHz. Higher up, it's difficult to achieve coverage. Again, other people already pointed this out.
If you want real news in this area, go to sites like this, or this. Slashdot's editorial quality has degraded in the last few years so much that I am thinking about deleting it from my bookmarks.
[/rant]First I thought how useless this is - Microsoft trying to modify Windows to sell a few dozen licences to run on dozens of different platforms (each supercomputer is custom-designed, no?). Also - the programs that run on these machines are just huge sets of calculations, and the operating system is irrelevant... you probably don't even need one...
But then I RTFM - they just setup Windows to simplify clustering. Linux has had that for long time. Nothing to see here, please move along.
In soviet russia, sun hurls at you!
Sorry, but they don't have the mentality to capture the subtle hilarity of the Hitchikers guide. It's like a industrial drill operator trying to do a brain microsurgery...
I'd like to be surprised though.
test - ignore
I said ignore.
I mean it.
Go away.
Most often by far, the digital signal processors are used in mobile phones these days. They are used for the speech compression and channel coding.
Would be nice to get more talk time...
If developers can choose the language to use (often the case when developing 'scripts'), the people that select Perl or Python will almost always outperform people who choose Visual Basic.
Languages are not equal. Perl, Python, etc. are designed for hackers by hackers. Visual Basic, Java, etc. are comitee designed languages for the incompetent.
BTW, it's possible to fuck up in any language, if you try hard enough...
In my experience, it's much harder to develop DSP software compared to developing hardware for the same task. Hardware design these days is a mature engineering discipline. Software development remains a high-risk black art, DSP doubly so. Also, for some signal processing tasks, the demand on processing power far outstrips the current processors. For something like a 3G modem you might need 20 Gigaflops to implement it in software. Even a plain well designed comms receiver from 20 years ago with a couple of crystal filters cannot be fully emulated with today's DSP technology. Complemented and enhanced - yes, but not emulated. How do you show that software-defined radio is up to more than just filling a very limited and specialised niche?
This is just a different method of sharing spectrum among different users. The currently used methods are pretty good. They have been under development for about 100 years. The Rf spectrum is a limited resource. The amount of information that can be transmitted over the spectrum is limited by Shannon's theorem (read his 1949 paper). This limit can't be increased. What UWB does is spreading its information over really wide bandwidth, raising the noise floor for everybody else. If there are enough UWB transmitters around, they will interfere with each other to the point of uselessness. Also, this will f**k up every other user of the Rf spectrum. In addition, with UWB, the spectrum can't be managed by assigning different frequency bands to different entities. Everyone jsut uses all of the spectrum all the time. The strongest transmitter wins. Sounds like this technology has a good chance of being approved in the US...
The author suggests that drivers have been left with little choice because all of the current cars only have four wheels and an engine.
Talk to them, maybe they are willing to rent some "underground" bandwidth?
while (in_space == 1)
{
if (Abs(speed_error)>threshold))
{
fire_thrusters(-speed_error);
msg_to_nasa("This is AI here. I have just corrected the speed! Send a news release.");
}
else
{
msg_to_nasa("This is AI here. Everything is OK.");
sleep(100);
};
};
msg_to_nasa("This is AI here. I have landed!");
... Since when do you call feedback "artificial intelligence"? Gimme a break NASA.
having no intelligence of it's own, it is no more a 'robot' than a bulldozer, controlled by a remote...
virtual reality? oh please, give me a break...
how to get publicity and funding: build a 1950s-sci-fi-style remote controlled mechanic toy in the shape of human body and call it a robot. then throw in a few passé catch-phrases like 'virtual reality' or 'fractal automata' or 'nano'-whatever...
Robin Williams was at least funny...
1) The sticks on the picture look like VHF omnidirectional antennae. Also, you only need large antennae when the satellite is far away, like geostationary orbit. On the Low Earth Orbit (~800km), all that is needed is a very small transmitter, comparable to a mobile phone in terms of power; well, at least for low bandwidth connections. There are quite a few tiny satellites like that in orbit right now. They are being used radio hams , scientific experiments, etc...
Another part of the answer is that dishes can only reasonably be used at microwave frequencies (above 1GHz), otherwise they would be too large
2) With omnidirectional antennae, there is no need for attitude control, see above.
If you really are into long distance, ham radio buffs routinely do global data comms.
:)
Advantages: * high power limits * plenty of allocated frequency bands from long wave to millimeters * fun * cheap
Problems: * no real 'networking'(all is manual connections) * not too high bandwidth * have to get licence (not too difficult though
The fact that the system uses DSSS (direct sequence spread spectrum) should minimize the interference. I wonder if anyone has done any real testing on how many networks can operate at the same time.