New Chip Promises Longer Battery Life

Roland Piquepaille writes "It always happens when you need it the most: the battery of your cellphone just died. But now, researchers of the University of Rochester have developed a wireless chip that needs ten times less power than current designs. 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. The new chip uses five transistors and can perform divisions by 3 instead of only 2 by previous circuits, allowing a perfect communication between two phones communicating at 2.0001 and 2.0002 gigahertz respectively."

Comments

Not A Big Deal

[Bruce Perens]

The PLL component this is supposed to replace is a small-signal component. It is not a major user of the power budget of a cell phone. The big power users are the transmitter and the microprocessor. The PLL is not heat-sinked and does not run warm. If it's not hot, it's not a power hog.

Bruce

Re:Not A Big Deal

[geoskd]

The PLL component this is supposed to replace is a small-signal component. It is not a major user of the power budget of a cell phone. The big power users are the transmitter and the microprocessor. The PLL is not heat-sinked and does not run warm. If it's not hot, it's not a power hog.

The Problem is not that the PLL uses lots of energy, the problem is that digital circuitry, which the PLL feeds, uses power that is proportional to the frequency at which the PLL drives it. If you have a digital circuit at 2 GHz, it will use one tenth of the power of a circuit which runs at 20 GHz. This is important because traditional digital circuits which communicate with each other on specific frequencies, do so by running a clock speed of at least 10 times the communication frequency, and then using a microporcessor to count up clock pulses in order to exactly equal the right frequency. If you are running at 10x the communication frequency, then you need to count ten clock pulses for each communication signal cycle. If you need greater accuracy, then you need more clock pulses per communication cycle to get that accuracy. Thus, your digital circuits are in effect running at much higher clock frequencies than are necesary to actually achieve the communication. This is why your little 2 watt tx/rx chip actually consumes closer to 20 watts when it is communicatng actively.

What these researchers have done is found a way to adjust the frequency of the digital circuitry to exactly match the communication frequency, so instead of counting pulses, we can safely assume that 1 digital signal cycle = 1 communication cycle. This is just as good as clock pulse counting when it comes to processing digital communication signals, but up until now there was no way to adjust the source frequency with any real accuracy, so you had to run the source frequency very fast and count up pulses to get accuracy. Now, we no longer have to count, we just use one pulse / cycle, and were all set.

To explain in a slightly different way, we'll use the analogy of trying to accurately count a mountain of pennies. The easiest way to do so, is to weigh the whole pile, and then divde by the average weight of a single penny, and you get the total number of pennies. The question is how you get the "average weight" of a single penny. If you weigh just one penny, and use that as the average, then you have some total inaccuracy X. If you instead weigh 10 pennies and divde the weight by 10, the inaccuracy is much less: roughly X/10. This is how the old method of PLL circuit design worked. The greater the frequency, the more pennies you used to find the average weight, and so the greater the accuracy you could get in finding out the total number of pennies in the whole pile, or the exact frequency.

The new method described in the Article is roughly analagous to modifying all of your pennies to ensure that the variation in the weights of the pennies is much lower, so you can rely on just one penny to provide you with the precision needed to determine the total number in the pile.

I hope this cleared up some of the confusion.

-=Geoskd

Re:Not A Big Deal

[Dis*abstraction]

Actually, I'm still a little confused. Could you try an analogy using cars instead? Thanks.

Re:Not A Big Deal

[chriso11]

No, the digital circuitry does not run at the PLL frequency in a cell phone. The stable reference frequency from the crystal is upconverted to what is called the LO - this LO is mixed in with received signal from the antennea to downconvert the signal to a lower frequency. No digital processing occurs at 1.8GHz/1.9GHz on a cell phone - it is all much lower in frequency. That also goes for Bluetooth and WiFi.

The article is really short on details. The real power hog in a cell phone is the transmitter - it will draw 3Amps of current - while the rest of the receiver and up-conversion components are maybe 10% of that. And transmitters are already quite efficient - generally, ~50% of the input DC power winds up going out as RF power.

The lower power version of the PLL will be useful, since it needs to run constantly, even while not actively in a call.

Re:Not A Big Deal

[alx5000]

To explain in a slightly different way, we'll use the analogy of trying to accurately count a mountain of cars. The easiest way to do so, is to weigh the whole pile, and then divde by the average weight of a single car, and you get the total number of cars. The question is how you get the "average weight" of a single car. If you weigh just one car, and use that as the average, then you have some total inaccuracy X. If you instead weigh 10 cars and divde the weight by 10, the inaccuracy is much less: roughly X/10. This is how the old method of PLL circuit design worked. The greater the frequency, the more cars you used to find the average weight, and so the greater the accuracy you could get in finding out the total number of cars in the whole pile, or the exact frequency. The new method described in the Article is roughly analagous to modifying all of your cars to ensure that the variation in the weights of the cars is much lower, so you can rely on just one car to provide you with the precision needed to determine the total number in the pile.

Re:Not A Big Deal

[Kent Recal]

How does this translate to libraries of congress?

Re:Not A Big Deal

[stevesliva]

I think part of the confusion is that this circuit is proposed to replace the PLL. The "digital circuitry" referred to that is running at the PLL frequency is the PLL itself, using a bunch of mixed-signal magic to take an input clock and spit out a very specific frequency. This new thigamabob proposes to take a very-high frequency quartz oscillator as an input signal and divide it down to a specific frequency using some analog magic. Although to say that this PLL replacement avoids digital logic entirely would imply no rebuffering of reference oscillator or clock anywhere along the line...

Re:Not A Big Deal

[kinzillah]

You could probably hire mexicans to count them cheaper than you could buy a scale capable of weighing a mountain of pennies. Along with that massive scale you would also need front end loaders and cranes, and union workers. Ideally, you could get the mexicans to feed them into those coinstar machines, though capacity may be an issue.

Re:Not A Big Deal

[fireweaver]

Bruce Perens: "The PLL component this is supposed to replace is a small-signal component. It is not a major user of the power budget of a cell phone. The big power users are the transmitter and the microprocessor. The PLL is not heat-sinked and does not run warm. If it's not hot, it's not a power hog."

But it runs continuously. Why else would the battery run down when the phone is not in use? Anything which minimises the standby drain on the battery is a Good Thing (tm).

Re:Not A Big Deal

[djupedal]

...try an analogy using cars instead?

If an end-to-end mobile phone system was a used Portland taxi, the meter would never come off polling, the user would be the rear view mirror and you would be an old penny lost long ago under the right front seat.

Re:Not A Big Deal

[Anonymous Coward]

This is why your little 2 watt tx/rx chip actually consumes closer to 20 watts when it is communicatng actively.

P=IV

Modern cell phones tend to run on 3.6V batteries. So 20 Watts at 3.6V requires 5.5555555555555555555555555 Amps, give or take a few decimal places.

Most standard cell phone batteries are rated at 950 mAh. Assuming you are correct on "20 Watts when ... communicatng", this would mean modern cell phones only get about 10 minutes of talk time. That's pretty low, so I can see why this new technology could be exciting!

I hope this cleared up some of the confusion.

It's always good to have a little bit of hope!

Re:Not A Big Deal

[Achromatic1978]

I would have said the LCD displays would also chew a fair bit of power - especially on phones like my Nokia N90 with two of them, one a very high res one (352x416). Not to mention people who are high users of accessories, in particular MP3 players and cameras.

Re:Not A Big Deal

[Proudrooster]

Cell phones have low power transmitters in the .5W to 3W of power range. A digital transmitter using a CDMA/TDMA scheme sends a transmission pulse every 6ms (or so), thus the power consumption is not continuous but works out to about 50% on, 50% off. I would have to look at my cell, but 20W of power consumption while transmitting seems very high and it seems like your head would definately notice the heat being generated by the phone, not to mention that the efficiency of the phones electronics would be a mere 10% (2W/20W = 10%).

This new 5-transistor frequency divison technique looks interesting, but it still relies on averaging and rounding which sounds like it will lead to imprecise clocking. I am still bitter that my PCs CMOS clock (RTC) can't keep decent time when running off battery. Maybe Wu's new method could help out there too. :)

Re:Not A Big Deal

[Jeff DeMaagd]

Another issue with your claims is that the power needed to operate a CMOS digital circuit goes up not linearly but by the square. A circuit that operates at 20GHz would consume about 100x the power as the same circuit that operates at 2GHz. I'm not aware of any commercial digital IC that can operate at 20GHz anyway.

Re:Not A Big Deal

[swiftstream]

The question is how you get the "average weight" of a single penny. If you weigh just one penny, and use that as the average, then you have some total inaccuracy X. If you instead weigh 10 pennies and divde the weight by 10, the inaccuracy is much less: roughly X/10.

Actually, you would expect it to be roughly X/sqrt(10). Standard error decreases with the inverse of the square root of the sample size.

Re:Not A Big Deal

[shawb]

Hell, you've got a mountain of pennies to pay them with. Just tell them they can take as many as they carry, but only if they tell you how many they took.

Re:Not A Big Deal

[djupedal]

The greater the frequency, the more pennies you used to find the average weight, and so the greater the accuracy you could get in finding out the total number of pennies in the whole pile, or the exact frequency.

You were doing ok until that part. It stands as contradictory with the next content, however...

The new method described in the Article is roughly analagous to modifying all of your pennies to ensure that the variation in the weights of the pennies is much lower, so you can rely on just one penny to provide you with the precision needed to determine the total number in the pile.

1.) 'roughly analagous' is redundant and also counts as one spelling error - (analogous)...in an otherwise decent piece of writing.
2.) Either you count some (few) or you count 'all'...counting 'more' is the same as counting 'all' - counting 'one' defeats the entire approach of using a statistical average, and is thus no longer statistically bound.

As long as you are using the option to modify, the logical process, rather than modifying towards an average weight, is to 'make' all pennies equal in known weight and not 'guess' via statistical averaging at all. Either force pile contents identicallity or move ahead based on averaging...don't use a process that consists of a mix of both methods.

And what is up with The Problem and the Article? Must be that mix of cut & paste and rewording that makes the entire submittal smack of internet plagiarism...say it isn't so :)

Re:Not A Big Deal

[AaronLawrence]

What a peculiar mish-mash of ideas. Where did you get them from? RF circuits don't work like CPUs. Just think about what you're saying: the CPU in your phone works at 2GHz? Yet the fastest CPUs in a PDA are about 500Mhz.

Re:Not A Big Deal

[Bruce Perens]

The backlight uses a lot of power, not the LCD. LCDs just modulate light, they don't emit it. oLED displays emit light. The backlit LCD or oLED display of a cell phone is an intermittent-use load with a duty cycle on the order of 1:1000, unless you use the phone as a PDA a lot.

Thanks

Bruce

Re:Not A Big Deal

[Achromatic1978]

Well, yes... the backlight. I would query the ratio of the duty cycle, though. My latest phone, I /do/ use as a PDA - but even before then, my cell phone would see a lot more than a minute of backlit activity a day. As a moderate user, I'd estimate 20-30 times that, at least, 1:50.

Re:Not A Big Deal

[Bruce Perens]

The receiver, not just its PLL, runs in standby mode. But even that does not have to run continuously, it just has to wake up often enough to make sure it doesn't miss an incoming call. I don't know enough about the GSM standard to say how long or often that is, but it could have a 1:100 duty cycle. The microprocessor has a low-power standby and might use only microwatts while waiting for an interrupt. That's how you get 200-hour standby times out of a battery with less than 4 Watt-hours total energy.

Thanks

Bruce

Re:Not A Big Deal

[MooUK]

To explain in a slightly different way, we'll use the analogy of trying to accurately count a mountain of Libraries of Congress. The easiest way to do so...

Re:Not A Big Deal

[kinzillah]

But that flies in the face of... the law... of... conservation of pennies!

Re:Not A Big Deal

[iamhassi]

"roughly analagous to modifying all of your penis to ensure that the variation in the weights of the penis is much lower..."

i'm very confused :-S

Re:Not A Big Deal

[blair1q]

And what is it in relation to the width of a human hair?

Re:Not A Big Deal

[john_uy]

what kind of car is it? are you going to average different kinds of cars or just stick with a single brand/model/make? that will introduce more errors. :P

Re:Not A Big Deal

[flogic42]

The speaker is as big of a power consumer as the processor. That's probably why most cell phones don't let you adjust the call volume as easily as you can adjust the ringer volume.

Re:Not A Big Deal

[lukestuts]

If you weigh just one penny, and use that as the average, then you have some total inaccuracy X. If you instead weigh 10 pennies and divde the weight by 10, the inaccuracy is much less: roughly X/10.

Er, not if your error is asymmetric and nonlinear, which is usually the case for dodgy lab equipment. Suppose your scale was introducing a positive error of +5 for each coin and this error increased by +1 for each five coins on the scale. With one coin, the error is +5. With ten coins, the error is +5 for each of the first five coins and +6 for each of the next five coins. When averaging five coins, the error is +5. When averaging ten coins, the error is +5.5. 100 coins is left as an exercise for the reader.

Know your errors.

Re:Not A Big Deal

[Anonymous Coward]

CMOS power scales with the square of voltage, not clock speed.

Changing the state of a CMOS logic gate requires charging or discharging capacitors. The energy stored in a capacitor of capacitance C charged to voltage V is equal to 0.5*C*V^2. Thus, if there are N state changes per second, the energy used per second is proportional to N*V^2 (we can assume that all the capacitors are roughly the same value). Power is energy per second so this is equivalent to saying that power is proportional to NV^2.

A clocked logic circuit's N figure is proportional to its clock frequency, since state changes are initiated by clock edges and little else. Thus, we arrive at power being proportional to fV^2.

There are some major complicating factors in today's advanced CMOS processes. All of the above assumes that the leakage current -- the steady state current which flows through gates even when they are not switching -- is essentially zero. That used to be true, but it sure isn't any more, which is the source of a lot of the scaling problems the industry first began to hit at 130nm.

Re:Not A Big Deal

[Bruce Perens]

The audio amplifier, you mean. But your point about adjusting the call volume is belied by the existence of handheld speakerphones, isn't it? I think the main reason for limitation of call volume is that they don't want to get sued for ruining your hearing.

Let's look at the audio a bit more. First, you don't really need a linear amplifier there, you can use a transistor in switching mode and low-pass filter the output. That's more efficient, and doesn't use any significant power during silent times. So, your power drain is going to be related to the duty cycle of speech, which has a lot of pauses, etc. Take 50 miliwatts for held-to-ear mode and cut that in half for a 50% duty cycle, and you get 25 miliwatts. Then consider that one of the CPUs (there are usually two CPUs, although they might be on the same chip - one, generally an ARM7, runs the GSM stack and the other, an ARM9, runs the UI and PDA functions) is probably running the GSM codec in both directions while the call is in progress. The CPU might still be using more power.

The transmitter, depending on its distance to the cell site (cell transmitters only use as much power as necessary for the link budget), could be putting out up to 600 miliwatts with about a 1:3 duty cycle and 60% efficiency.

Bruce

division

[Anonymous Coward]

"he new chip uses five transistors and can perform divisions by 3 instead of only 2 by previous circuits, allowing a perfect communication between two phones communicating at 2.0001 and 2.0002 gigahertz respectively."

But what does it mean? Since when do you need to divide by 3 instead of 2?

"ten times less power"?

[oldenuf2knowbetter]

Would "ten times less power" be anything like "one tenth as much power"?

Re:"ten times less power"?

[Paradise Pete]

Would "ten times less power" be anything like "one tenth as much power"?

At least. It might one eleventh. Numerical comparisons using less and more, rather than the accurate "as much" form, tend to be ambiguous.

Re:"ten times less power"?

[Paradise Pete]

Stick a "be" in there for me, would ya? Anyway, as long as I'm following up on my own post, I'l try to restate it in a less pompous way. What would "two times less" mean? It certainly shouldn't mean half as much, but it would have to in order to be able to state one tenth as "ten times less." So the original comparison form is simply broken.

Re:"ten times less power"?

[NewbieProgrammerMan]

Wish I had mod points for you....assuming you meant that to be funny, of course...

Re:"ten times less power"?

[Anonymous Coward]

It means it can power 9 of the current chips.

Re:"ten times less power"?

[Paradise Pete]

Well I almost always mean to be a little funny, even when I'm trying to make a point. But that "two times more powerful!" stuff is a pet peeve of mine. And every once in a while it gets out of its cage. (There. that last part was me trying to be a little funny. Very little, I know.)

Re:"ten times less power"?

[Guuge]

Imagine all the power the old chip doesn't use. Multiply this number by ten. This is the amount of power the new chip doesn't use. So you end up not using ten times as much power as you used to not use.

Re:"ten times less power"?

[mattcoz]

No, it would be "negative nine times as much power", so we're talking infinite battery life, truly a breakthrough.

Re:"ten times less power"?

[Anonymous Coward]

Negative power isn't the same as zero power, you idiot. Using the phone a negative amount of time *will* drain the battery.

Re:"ten times less power"?

[alexmipego]

Would "you" be anything like "a human"?

Re:"ten times less power"?

[swordfishBob]

only if it's 97% fat-free

Re:"ten times less power"?

[squiggleslash]

Not at all. The device is so efficient, that if it replaces something that would usually run at one watt, it actually ends up running at -9W, generating power. Not only will this help with mobile phone battery use, but it also means we'll be able to power our homes, vehicles, and other necessary appliances using magical mobile phone technology rather than traditional, more dangerous, systems in the future.

Conversation

[LiquidCoooled]

Dude: Hui Wu invented this new chip that saves loads of power.

Bloke: Who?

Dude: Yes

Bloke: so who invented this chip.

Dude: Hui did.

Bloke: Thats what I'm asking you.

Dude: Yer I know, Hui did.

Bloke: Quit it and tell me who invented the chip.

Dude: Im not joking, Hui did.

Re:Conversation

[jdbartlett]

Oh no, not again.

Re:Conversation

[ralph alpha]

Too bad the joke is invalidated because "Hiu" isn't pronounced like "who."

Re:Conversation

[Anonymous Coward]

I believe it is pernounced more like "Hwee" than like "Hoo-ee".

Re:Thats interesting and all

[Bruce Perens]

The various segments of the readout are wired in a sort of square matrix to save wires at the chip outputs and driver transistors inside the chip or on the circuit board. They can't all be on at once because of the wires they share. They have to be driven in sequence. So, you see a sort of strobe light effect where each different part of the number is flashed at a different point while your head and eyes vibrate in a sort of arc.

Bruce

Battery power

[cr@ckwhore]

"It always happens when you need it the most: the battery of you cellphone just died. But now, researchers of the University of Rochester have developed a wireless chip that needs ten times less power..."

Ok, but that still doesn't solve the "I need my phone now but I was too lazy to charge it last night" problem. So what, this chip can run from a dead battery? No.

It really doesn't matter how much power the phone uses... the fact is that it still uses power. Consuming power from a limited source means that it will reach a point when the battery is depleted, except now it just takes 10 days longer than before.

Murphy says, you will still be inconvenienced.

Re:Battery power

[MobileTatsu-NJG]

"It really doesn't matter how much power the phone uses... the fact is that it still uses power. Consuming power from a limited source means that it will reach a point when the battery is depleted, except now it just takes 10 days longer than before."

You're absolutely right. I don't even know WHY they're bothering! *places hands on his and sadly shakes his head*

Re:Battery power

[jdbartlett]

You are correct in saying cellphones use electricity. You are incorrect in saying this does not solve the I was too lazy to charge it last night problem. It does. It does not, however, solve the I was too lazy to charge it last week problem. Still, I'm sure you agree, it's a step forward. Eventually, we'll design cell phones powered by thought. I have one interesting device that has enabled me to communicate up to hundreds of feet using no electricity. Just gives me a bit of a sore throat is all.

Re:Battery power

[Anonymous Coward]

[i]Eventually, we'll design cell phones powered by thought.[/i] Not likely, this cuts off their core demographic. Posting anonymously so as to not undo moderation. NemosomeN

Re:Battery power

[NemosomeN]

Undoing moderation to Comment #15182575
Undoing moderation to Comment #15182612
Undoing moderation to Comment #15182623
Undoing moderation to Comment #15182652
Undoing moderation to Comment #15182671

Fuck. I totally fucked up last post. Guess I shoulda logged out.

Re:Battery power

[Anonymous Coward]

So it was you who moderated this subthread "offtopic"? Sure, it's technically true--but you're still a petty asshat.

Re:Battery power

[mikej]

It does matter how much power the phone uses. Your phone using 1/10th the power, which is ultimately from the same source as all your domestic energy, means almost nothing; A million, 10 million, or 100 million phone users all using 1/10th the power, well... it adds up. Sure your use profile isn't going to change, but you get the same utility for less power. That's basically the modern definition of Good.

Re:Battery power

[NemosomeN]

I modded the "This isn't off-topic" as "Off-topic" and the parent as "Interesting," actually. Asshat.

Re:Battery power

[Anonymous Coward]

Haha, this little exchange got me [NemosomeN] a foe. lawl. DrunkenTerror needs to grow up.

Why are we still using batteries?

[El Cubano]

But now, researchers of the University of Rochester have developed a wireless chip that needs ten times less power than current designs. The new chip relies on a technology named injection locked frequency divider (ILFD) and permits to dramatically reduce the time needed to check for transmission frequencies which are performed several billion times per second by your current phone.

Out of curiousity, why have we not yet figured out how to wirelessly power devices? I mean, we can send lots of RF energy through the air. Why can we not use that same energy to power the device as well as send it information? I can see where it would be a problem for something that requires lots of power, but for small devices this should be possible, no?

Re:Why are we still using batteries?

[stevesliva]

I mean, we can send lots of RF energy through the air. Why can we not use that same energy to power the device as well as send it information? I can see where it would be a problem for something that requires lots of power, but for small devices this should be possible, no?

Dude, you just re-invented RFID tags! You'll make me smile next time I unlock the doors at work.

Re:Why are we still using batteries?

[Anonymous Coward]

We can, but not for something as power-hungry as a cell phone that needs a transmitter capable of communicating with a base station a mile away. It takes a lot of energy.

Re:Why are we still using batteries?

[El Cubano]

Dude, you just re-invented RFID tags! You'll make me smile next time I unlock the doors at work.

OK:

1. Coffee first
2. Post on Slashdot second

Re:Why are we still using batteries?

[Anonymous Coward]

Because enough power to run your laptop will likely cook bacon?

Re:Why are we still using batteries?

[m85476585]

If you have a 2-way radio (I don't know if a cellphone would work), go to Radioshack and get a low-current light bulb (not LED) and connect solid leads about 8" long to each lead of the bulb. Make them both into a coil, slip one over the 2-way radio antenna, and transmit. The lightbulb should glow bright. Unfortnately RF energy decreases as inverse square.

Re:Why are we still using batteries?

[Com2Kid]

Out of curiousity, why have we not yet figured out how to wirelessly power devices?

Short answer: We already have, it is just so inefficient that nobody uses it. (in fact it was invented over 100 years ago!)

Long answer: Electromagnetic waves radiate outwards. Either you have a simple non-directional antenna that radiates in all directions at the same time (in a sphere basically) and you lose power REALLY fast, or you have a directional antenna that radiates power in a cone at a target destination.

The omni-directional radiators suck so much that they are absolutely useless. Inverse square means 1/(x^2). Basically (and this is crappy math but gets the point across) if you have 10 watts at 1 feet, you would have 10*(1/(2^2)) = 2.5 watts at 2 feet. At 3 feet you would have 10*(1/9) = 1.11 watts. Please ignore that you would use meters instead of feet and that all my units are all messed up in various other ways as well. The point is that your power drops off REALLY fast.

So what about those directional antennas?

Well, you have to find some way to really accurately track someone's cell phone position, and have a world-wide array of directional antennas so that you can beam power to them no matter where they are at.

Oh and remember to keep those power levels low, else you will fry anything that gets in the way.

People worry about cell phones causing cancer as it is, directional power beamed at your head WOULD cause some serious issues!

Wireless power is possible, just not feasible!

Re:Why are we still using batteries?

[PopeRatzo]

But won't all that power floating around in the air cook all the birds?

Re:Why are we still using batteries?

[Anonymous Coward]

I can see where it would be a problem for something that requires lots of power, but for small devices this should be possible, no?

On the other hand, I can see where it would be a problem for something that has a small RF cross-section, but for large devices this should be possible, no?

Re:Why are we still using batteries?

[LoverOfJoy]

It could make a cool watch, though.

Re:Why are we still using batteries?

[Bloater]

Is it that all that 7.5 Watts is dissipated by the transmission distance increasing from 1ft to 2ft? Or is it that the EMF at the receiver reduces by distance^2?

Re:Why are we still using batteries?

[darthwader]

A while ago, Mythbusters did a "free energy" show. They collected a bunch of plans from "the Internet", built the devices, and tested them.

One of the devices that surprised me was a 50' long aerial, attached to some simple circuitry. The aerial absorbed RF energy, and the electronics converted it into a somewhat useful DC power supply. I think it was producing somewhere around 1 volt, no idea how much current, indoors. IIRC, they said it was "almost as good as a AA battery".

So, not only is is possible in theory, it's possible in practice. But it's still wildly impractical.

I think it's episode 24 (http://dsc.discovery.com/fansites/mythbusters/epi sode/episode_06.html).

Re:Why are we still using batteries?

[livewire98801]

So, we solve the world's hunger problem along with DC power problems. . . talk about killing two. . . [clears throat]

Re:Why are we still using batteries?

[mikiN]

Out of curiousity, why have we not yet figured out how to wirelessly power devices?

Well, there's this great ball of fire boiling away in space that sends part of its goodness our way, the most obvious way to wireless energy transfer.

Trouble is, not many devices are taking advantage of it yet (apart from watches, calculators, environment monitors and the lot), partly because of power requirements being too high, partly because of lack of cheap and efficient solar panels.

Of course, if you live in a sunny place, you could buy a solar power battery charger for your phone.

Re:Why are we still using batteries?

[Anonymous Coward]

Killing two birds with one phone?

Re:Why are we still using batteries?

[Com2Kid]

Since we are talking about spherical radiation the energy is still there, it has just been radiated in, literally, every other direction.

Err, it makes a lot more sense when drawn on a board. :) The 1/x^2 thing is actually just due to the surface area of a sphere. (as I said, I dropped a ton of constants out!)

You can imagine in that you have "X watts" that are initially bundled up in a single point (the round little tip top of the radiating antenna, which in perfect physics land, is a single point. :).

Because EMF energy is radiated in a sphere when coming from a single point source, you have this ever increasing sphere. You basically have to "stretch" those "X watts" out over the surface area of the sphere.

(my humble apologizes to any actual physicists out there!)

Re:Why are we still using batteries?

[Schraegstrichpunkt]

IANAPhysicist, but to put it another way, if you take an omnidirectional antenna, and draw a sphere around it, the total energy over that sphere will be the same, regardless of the distance. However, the energy density (e.g. energy per square foot) decreases drastically as distance increases. Since the receiving antenna has a fixed size, the amount of energy captured by your antenna decreases equally drastically.

As you said, it's pure geometry.

Re:Why are we still using batteries?

[null-sRc]

you don't think cell phones cause enough brain cancer? now u wanna send power to them too :|

Re:Why are we still using batteries?

[Anonymous Coward]

Out of curiousity, why have we not yet figured out how to wirelessly power devices? I mean, we can send lots of RF energy through the air. Why can we not use that same energy to power the device as well as send it information? I can see where it would be a problem for something that requires lots of power, but for small devices this should be possible, no?

I like my balls, thank you very much.

Re:Why are we still using batteries?

[zippthorne]

Yes. Actually, your sphere technique will work for a directional antenna as well. The directionality of the antenna will determine just how that energy is distributed, since it's not even over the whole surface, but the inverse square law holds regardless of the radiation pattern.

Re:Why are we still using batteries?

[Tsukki]

Also, Nikola Tesla theorized you could use the Schumann resonance to beam energy around the world with little resistance, but the project was dropped about 30 years ago for unknown reasons.

Re:Why are we still using batteries?

[Anonymous Coward]

Brilliant, so now we can stop using those pesky AA batteries, which are so heavy and take up lots of space. All we have to do is carry around 50 foot aerials instead. :)

Re:Why are we still using batteries?

[milimetric]

they said it was "almost as good as a AA battery"

eghads Brain... imagine a beowulf cluster of these things. You could use it to decode the very rf signal that powers them thus creating a sustainable way to spy on everyone and thus please both the liberals and the conservatives at the same time... and then TAKE OVER THE WORLD.

Re:Why are we still using batteries?

[ScrewMaster]

What, it would bother you if your children were born with long, green tendrils coming out of their foreheads?

Billion?

[sapgau]

Like in gazillion?

Re:Billion?

[Schraegstrichpunkt]

In America, we call it a gajillion. You're clearly not with us, here. (Does that mean you are with the terrorists? Hmm?)

Re:Thats interesting and all

[Anonymous Coward]

Try reading a CRT while using an electric toothbrush. Wacky.

Re:Thats interesting and all

[hackwrench]

Because they are all red, and red bends more than other colors.

Re:Thats interesting and all

[Anonymous Coward]

You have brain cancer. Check into a hospital immediately.

Re:Not(?) A Big Deal

[thestuckmud]

I don't use my cell phone much. Having several weeks of standby time would be convenient, even if talk time is not increased significantly.

Re:Thats interesting and all

[Dis*abstraction]

Because loud noises, such as from crunchy foods, jiggle the electronics in the LED. The same thing happens when you sneeze, if you can keep your eyes open to watch.

Re:Not(?) A Big Deal

[green1]

the problem is, even in "standby" the phone does a lot of transmitting, and that transmitting is still a power hog.

I'm not quite as negative as the grandparent poster, in that I'm happy if any component uses less power (every bit helps) but in reality, it's the transmitter that uses the lions share of the juice, not the reciever (even in standby).

Re:Thats interesting and all

[sqrt(2)]

Hey mods, this isn't off-topic. Only a top level comment can be off topic, this answers the question in the parent and thus is on topic.

Two/Three

[samkass]

The new chip uses five transistors and can perform divisions by 3 instead of only 2 by previous circuits

Bender: "Ahhh, what an awful dream. Ones and zeroes everywhere... and I thought I saw a two!"
Fry: "It was just a dream, Bender. There's no such thing as two."

wind up?

[Anonymous Coward]

We have wind-up flashlights, why cant we have wind-up cellular phones?

do they take more power than a flashlight? what if i wound it for 5 min instead of 2? would that be enough?

One idea

[thePig]

The transmitter would be the one which would be using the max power in any cellphone.
In that case, make the antenna directional.
But then, we do *not* know the direction to which I have to sent the signal.
That can be done by maybe -
1. Changes needed for Towers
      Sent downstream a small pilot signal of the same freq as the upstream signal which the phone emits for that call.
2. Changes needed in the Cell
      Have a direction sensor in your mobile for this pilot signal. Once direction the highest amp for the pilot signal is obtained, sent the signal back in the same direction.

Instead of the wasted signal going all around, we have a signal which has very good directional properties. Thus the power of the signal to be sent can be reduced to maybe even 1/10th or 1/100th.
Thus the battery life also will have a propotional increase.

Adv of this system -
1.We dont care how many changes in direction the signal took and all.. Since the pilot came this way, my signal (almost the same freq, so almost the same refractive/reflective properties)will reach the tower proper.
2. Worries about your head getting fried by signal now over. Supposing that your head occupies 90 degrees of the phone directionality, now there is 1/4th time the power goes through you. In anycase, I dont think there is a high probability of the max amp pilot signal coming through your head.. So much less say1/10th of the time upstream signal goes through you.

Prob -
Changes needed in all towers.
Is a antenna which can change direction depending on a signal already there ? If not the idea wont work at all.

Just an idea.

Re:One idea

[scruff323]

One problem: In this case, you couldn't turn around while talking, you would have to remain in the same position basically for the whole time. This seems like a big pain in the ass. I pace all the time while talking on the phone.

I say just get rid of all those extra features like color screens and cameras if you are worried about battery life. My phone is an old LG phone without color or fancy ring tones and stuff. The battery can literally last 4 or 5 days on standby.

Re:One idea

[planetmn]

Is a antenna which can change direction depending on a signal already there ? If not the idea wont work at all.

A combination of multiple "antennas" with a 120degree coverage (for three) rather than a single antenna with 360 coverage, and phased array (look at phased array radars) could make this possible. Power savings though, might not happen because of the processing required.

-dave

Re:One idea

[thePig]

Why ?
We can turn around.
The pilot signal would be coming full time. So the signal direction where it is sent also will be changing full time.
This is a real -time system, which I trying to concieve.

So methinks no issues in this regard

Re:One idea

[snilloc]

Lasting 4-5 days on standby isn't spectacular. My old monochrome nokia used to do it (until the battery started flaking out after 3 years of continuous use). My brand new samsung model (with color screen, external display, and funky ringtones) has been doing about that much, and weighs 2/3 what the Nokia did.

More to your original point however, it wouldn't be unthinkable to have a monochrome display on a very basic phone and have it last ten days with current battery technology... but almost nobody (save for you and me) would buy the phone.

Re:One idea

[woolio]

Is a antenna which can change direction depending on a signal already there ? If not the idea wont work at all.

Yes, it is possible to have a directional antenna without it physically having to move in order to change directions. I think they have been around for a long, long time. Mutliple antennas/elements are required. (phased array?) . But the consumer wants a cell phone, not a porcupine.

I *think* something might be done like this in current MIMO research. I believe the problem of finding the direction is more complicated than just a pilot tone. It usually required multiple antennas and gets confused by multipath. (e.g. which one do you aim at)? I have briefly heard of MIMO guys using multiple antennas and doing beamforming with them.

Also, what happens if someone in a car,train, etc? (changing angles at high rate of speed). I wonder how well existing hand-off algorithms would work with directional antennas.

Also, it would seem that a directional phone would be forced to use lower transmit power (so that the max Effective Radiated Power to the head was the same/lower).

Also for cell phones, I wonder if directioality would be limited to 2D or 3D? (after all, the towers are usually fairly close by).

Re:One idea

[letxa2000]

As someone else said, it doesn't much matter if it lasts 10 times longer or not. At some point, if you don't charge it, you're going to run out of power.

I just charge my Treo each night when I go to bed. I use it as my alarm clock so when I set my alarm, I make sure it's plugged in and charging. I've never gotten below about 70% even on heavy-talk days. If it could use 10% as much energy, I guess that would mean that at the end of the day I'd be at 97% instead of 70%. But it doesn't really matter either way as long as I charge at the end of the day.

Re:One idea

[thePig]

Thanks. Let me try to answer one by one.

1.But the consumer wants a cell phone, not a porcupine

This was just an idea. Maybe with good research down the line, the size and look of it might get better

2.I believe the problem of finding the direction is more complicated than just a pilot tone. It usually required multiple antennas and gets confused by multipath.

Quite true. I also was thinking about two rxr antennas with different directional properties looking for the pilot tone. But this idea here would not be using multipath transmission.. even though MIMO does provide better txn properties.

3.Also, what happens if someone in a car,train, etc? (changing angles at high rate of speed).

A very valid point. If the current alogorithms are not capable of very fact TO time, maybe we might have to have a mechanism (using the cell datum from towers) to understand that we are *indeed* travelling at very speed, so turn off the directional txn for now.

4.Also, it would seem that a directional phone would be forced to use lower transmit power

Not exactly. The plan anyway was to transmit with the same power itself. Just that the beam would be directional.

5.Also for cell phones, I wonder if directioality would be limited to 2D or 3D?

A very valid point. Especially in cities. This is becoming much more complex now. I did *not* think about this one at all.

Summary - Your points, esp 3&5 makes the antenna construction for such cases makes it very complex, ungainly (multiple antennas with different properties), high processing power etc etc :-(

I *knew* (cough cough) that there should be some reason they did not go for this. Now I actually know.

But even then I am thinking with better processing power, these problems can be solved.

Maybe I am just optimistic.

Anyway, thanks.

Re:One idea

[woolio]

I did forget to mention that beamforming could be used by the cell towers... (and I think this is being researched)

Which would probably have all of the advantages that you were thinking about. If the tower can be more sensitive, then the cell phone can use less power, etc.

The towers also have the benefit of extra room for antennas, extra processing power, and might even be able to collaborate to determine the direction to the cell phone (e.g. as being done for 911)

Respectively?

[General Wesc]

The new chip uses five transistors and can perform divisions by 3 instead of only 2 by previous circuits, allowing a perfect communication between two phones communicating at 2.0001 and 2.0002 gigahertz respectively.

Respectively? Are you saying the 2.0001 divides by 3 and the 2.0002 divides by three? But they both can divide by either, is the point, right?

(Am I just begging for a 'You must be new here' post for not instantly assuming it's just lack of good editing?)

Re:Respectively?

[Anonymous Coward]

The point is dividing down from a terahertz reference by powers of 2 alone allows 500 GHz, 250Ghz, 125Ghz, etc... Can't get to 2.0001GHz.

Dividing down from a terahertz by numbers that are factored down to 2 and 3, however, may allow you to get 2.0001GHz -- haven't bothered to figure whether a terhertz is fast enough.

Re:Thats interesting and all

[ltbarcly]

The red cones in your eye react more slowly than the other color receptors. Therefore when you are looking at the red led, which is a pure red light surrounded by darkness (not common in nature btw) what you are actually seeing is the vibration due to the crunch momentarily after they happen. Your brain adjusts so that you do not notice the vibration in your vision, except it cannot take into account the slight delay in the red cones. Therefore the red light appears to jump around.

When you date triplets.

[Naruki]

Not a common thing, but when it happens... Pixpls.

Re: usb to 9v battery charger

[cheekyboy]

Make a 9volt USB battery charger

http://www.hackaday.com/entry/1234000520028239/

Or a WIND UP charger

http://www.edirectory.co.uk/pf/pages/moreinfoa.asp ?pe=CBHJGEGQ_+mobile+phone+wind+up+charger&cid=880

or a WIND TURBINE PHONE CHARGER

http://www.bytesurgery.com/gearedup/2006/02/a-wind -powered-phone-charger.html

But would I have to stand still?

[PopeRatzo]

Or keep the phone oriented in the same direction? And what's this about frying your head? My girlfriend is always on her cellphone. Oh.

"Ten times less"

[Anonymous Coward]

What the hell does "ten times less" mean? If it uses 1 watt now, does that mean it now uses 1 - (10 * 1) = -9 watts? So using htis actually generates energy?

Re:"Ten times less"

[Anonymous Coward]

Okay Mr Pedantic Idiot, I guess you need a lesson in English. Ten times more means you take the number, it's more than, multiply it by ten--that's your number. "Ten times less", the opposite of "ten times more", means you do the opposite of that, In other words, you would take the number and divide it by ten. The alternate construction, "a tenth as much" is also acceptable, however it requires a complete rephrasing.

Re:"Ten times less"

[Anonymous Coward]

Okay, you marketing department moron, I guess you need a lesson in basic third grade story problem arithmetic. "Ten times" means you take ten times the first number. "More" means you add it. Thus, "ten times more" is actually eleven times as much. "Less" means you subtract it. This is basic third grade story problem math.

"X times less" is pretty much never used appropriately. I can accept arguments about the meanings of words changing because people use the wrong definition more than the right one. When you're talking about mathematical concepts, though, there's no excuse. You just can't make mathematical untruth true, no matter how large a percentage of the population's minds are too addled to know the difference.

Re:"Ten times less"

[xornor]

Like he said, pedantic...

Re:"Ten times less"

[acramon1]

"X times less" is pretty much never used appropriately. I can accept arguments about the meanings of words changing because people use the wrong definition more than the right one. When you're talking about mathematical concepts, though, there's no excuse. You just can't make mathematical untruth true, no matter how large a percentage of the population's minds are too addled to know the difference.

Perhaps, but the representation of a mathematical truth can change when people start incorrectly using those currently in place.

So if people start using "X times less" differently, it doesn't change the mathematics, just the translation of the English representation of it to the mathematics.

What a crock

[amjohns]

This is mostly BS. First off, the PLL is a small fraction of the power consumed by a modern phone, even though it is running all the time. Far more power is consumed in the rest of the receiver chain, from the LNA (low nose amplifier) and the digital demodulator. And no, this does not do a thing to minimize the demod, as it is running all the time too, to detect an incoming call notification.

Second, the statement that a "phase-locked loop multiplies the pulse from a highly-stable reference clock, such as a quartz crystal oscillator, up to the desired frequency" is 100% false. The function of a PLL is to lock (in phase...) a divided down version of a totaly independent RF oscillator, called a VCO, to a divided down version of the reference clock. The distinction may appear subtle, but it's enormous. Multipliers are large, power consuming IC's, while dividers are fairly small and efficient. There are NO multipliers in a PLL, period. Also, PLL's can already do split division, it's called a fractional-N PLL.

Mobile, battery powered electronics will never achieve decent battery life beyond a few GHz. There are several effects coming into play, from cosmic noise to H2O and O2 molecular resonances to increased multipath effects, and most importantly path loss. RF power spreads in a spherical wavefront, so there is a 1/R^2 power falloff. BUT, you need to recognize that this is in terms of wavelength (lambda), which is mathematically equal to C/f (speed of light / frequency). The net result is that doubling the frequency on a radio link incurs a 4-fold power fallof for a fixed distance.

So if I want to go from say just under 2GHz w/ a current GSM system to say 8GHz, then I need an effective 16 times the power output from my transmitter. I say effective, because you can use antenna gain, but not in the mobile handset (it needs to be omnnidirectional), and base stations directionality is very limited, since they need to support many users on the same antenna, and can't steer the beam to all of them simultaneously. You wouldn't be allowed ot put out that much powr form a safety perspective, never mind the power consumption and heat requirements in the power-amplifier. Handsets are at 600 milli-watts now, we're not going to put out >10 watts!

Re:What a crock

[Compuser]

So, if I may ask, why do you say that "battery powered electronics will
never achieve decent battery life beyond a few GHz"? It would seem that
as base stations grow in density of coverage we will be able to drop
power requirements. Imagine a base station every 10 m (like e.g. in
every lamppost). Already today cell phone coverage is only good in
civilized places, i.e. where roads go, so this would not drop
quality of service compared to what we have now.

Re:What a crock

[Luveno]

Every once in awhile, someone comes along with a post that restores your faith in /.

Re:What a crock

[zippthorne]

inverse square law is proportional to wavelength? Where did you ever get this wacky idea?

The inverse square law is so because it describes the effect of the expanding wave front as it propogates through space. The energy of any particular shell is constant, but as the shell expands the energy becomes more spread out. The square law is a consequence of our three dimensional space. The area of a sphere (the pattern of a so-called isentropic radiator) is pi*r^2, so the unit density will be {something}/pi*r^2 which is just {const}/r^2. Furthermore, the inverse square law works for all radiation patterns, not just spherical. It becomes {const}*f(theta,phi)/r^2 where f(theta,phi) describes the shape of the wavefront.

Further furthermore, At the higher frequencies, the base station antennas can be a much tighter beam. You could increase the number of elements (cells are already composed of an array of directional antennas on one tower in part to maximize the number of possible connections on one tower)

Now it is true that transmittance is a problem at higher frequencies, but this too is completely unrelated to inverse square law, and entirely related to composition of materials in the path of transmission.

Assuming the noise has a constant amplitude (and not a constant power, or even a more complicated function.. so basically, assuming incorrectly...) then the higher frequency noise would be a problem, but it would be just one more multiplier in the transmittance equation, completely affected by the inverse square law. (based on my quick back-o-the envelope calculation, I believe it would be linear. E=h{nu} => P={const}*f)

So, for a system in which the only thing you change is the frequency, in order to maintain the same S/N ratio, you must increase the power by a linear factor, but this would be offset by square-law tightening of the beam as a result of the increased frequency.

IOW, under your constant noise scenario, the power required *decreases* linearly with increasing frequency.

Re:What a crock

[thestuckmud]

RF power spreads in a spherical wavefront, so there is a 1/R^2 power falloff. BUT, you need to recognize that this is in terms of wavelength (lambda), which is mathematically equal to C/f (speed of light / frequency). The net result is that doubling the frequency on a radio link incurs a 4-fold power fallof for a fixed distance.

Sorry, but this last point is wrong. The inverse square law for power is, indeed, in terms of power, not wavelength. Actual radiated power depends on the power input to the final stage of the transmitter times the efficiency of that stage, the transmission line, and antenna. It does not drop simply because of an increase in frequency.

Wavelength and frequency are related to a photon's energy, by the equation e = h*f (= h*c/lambda), but this is not relevant here.

Your physics inspector (and amateur extra, AB0VV)

Re:What a crock

[randyest]

I hope you're not referring to the parent, since he's totally wrong. PLLs certainly can, and do, include multiplers (and/or dividers.) They're called . . . wait for it . . . "multiplying PLLs" (as opposed to "clock-insertion-delay removing PLLs." He also botched his bit about the inverse square law (on multiple levels.)

Re:What a crock

[C.A. Nony Mouse]

This is mostly BS.

No. It's some fine circuit research work, overhyped by a tech writer who didn't understand it well. (I'm a circuit researcher.)

First off, the PLL is a small fraction of the power consumed by a modern phone, even though it is running all the time. Far more power is consumed in the rest of the receiver chain, from the LNA (low nose amplifier) and the digital demodulator.

RF PLLs need lots of power to meet phase noise performance specs. Thus, you don't want to run an RF PLL all the time if you can get away without it; and in a TDMA system such as Bluetooth or GSM, you can. The trick is to turn the RF PLL and the rest of the receiver on only during time slots when there will/might be data intended for you. Another, slower and much more power-frugal oscillator will determine when to turn on the RF PLL.

And no, this does not do a thing to minimize the demod, as it is running all the time too, to detect an incoming call notification.

Not necessarily. In GSM, for example, incoming calls are signalled at comparatively long intervals (many milliseconds). If you don't turn off your receiver in the interim, your standby time will suffer mightily.

There are NO multipliers in a PLL, period.

You are right, but so is TFA, broadly speaking. The PLL itself acts as a frequency multiplier, it does not contain one.

Re:What a crock

[zippthorne]

Ok, maybe you can explain this though..

The article keeps talking about clock pulses. So.. The carrier is being generated as a square wave? It would seem to me that a lot of energy is being lost on filtering edges.

What's going on here?

Re:What a crock

[Detritus]

See the Friis Transmission Equation. Doubling the frequency results in a 6 dB loss at the receiver. So the signal strength is proportional to the square of the wavelength.

Re:What a crock

[zippthorne]

Your application of the Friis equation is incorrect. Antenna gain in the directional antenna depends on wavelength with a 1/lambda^2 factor.

Re:What a crock

[petermgreen]

i've never been to america so i dunno how poor thier coverage is, but i've only been to a few places here in the uk where mobiles didn't work

whereas with a 10M range like you propose even if you put one in every lamp post you'd lose coverage as soon as you walked to the middle of a small park or down an unlit sideroad.

Re:What a crock

[Detritus]

I don't see how. A given antenna, say dipole or isotropic radiator, becomes less effective as the frequency is increased. I'm assuming that is the source of the frequency dependent part of the equation. So other things being equal, increasing the frequency also increases the path loss.

Re:What a crock

[zippthorne]

Slashdot does not have convenient math notation, which would be required for the lengthy explanation of what's going on. But your assumption is incorrect. The key words to look for are "aperature size" and "effective aperature size" and note what happens in the case of isotropic radiator. It is also important to keep in mind that only one of the antennas in the cell phone/tower loop is isotropic.

Well, I *used* to be an RF engineer...

[Anonymous Coward]

... until my head exploded.

Move along, nothing to see here (cleanup on Aisle 12!), move along.

Re:Thats interesting and all

[Anonymous Coward]

Sorry but moderation is with respect to the story, not thread.

You are right. The article and parent are wrong.

[Anonymous Coward]

The article implies that the transmit frequencies are being checked at a 2 GHz rate. The parent implies that there is something in the cell phone with a clock rate of 20 GHz. Both are wrong. You are right. There is no digital processing at anywhere near that frequency.

There are two issues about frequency. One is precise control of the transmit frequency. It is, as you point out, done by a phase locked loop. The other issue is which frequency to transmit on and that is negotiated between the cell and the phone. The transmit power is also negotiated between the cell and the phone.

Actually, there is a lot going on. It would be pretty much impossible to build a modern digital cell phone without using some kind of processor. If you were to try to implement the same functions with discrete circuitry, your cell phone would probably weigh ten pounds. Given all that is going on, it's impressive that cell phone batteries last as well as they do. As you point out keeping the clock rate as low as possible is what achieves that.

Hiu as 'he'

[hackwrench]

Funny, I thought he was trying to pronounce Hiu as 'he'

actually

[cparisi]

The battery in me cell phone lasts quite a long time...

Re:actually

[Rashdot]

The battery in me cell phone lasts quite a long time...

Yes, it's lonely having the latest phone when nobody ever calls you.

Re:Thats interesting and all

[Anonymous Coward]

I just spent the better part of the last two months springing my brother from jail in Guangdong province, China. Your inflexibility and deference to "the system" and its undefined rules remind me of the behavior of the Chinese authorities.

get your pronounciation right

[nihaopaul]

hui should be pronounced like `hway`

Re:get your pronounciation right

[phlipped]

1: "Hoo" invented this new chip
2: No "Hway"!
1: YES way!
2: That's what I said
1: What?
2: The name of the guy is pronounced "Hway", not "Hoo"
1: Oh. I thought it was "Hoo"
2: No it's "Hway"
1: I see
2: Yes. Well ... Um ... I have to go ... over ... there now
1: Ok ...

Re:get your pronounciation right

[nihaopaul]

hui to go!

Re:get your pronounciation right

[cciRRus]

hui should be pronounced like `hway`

It's pronounced as "h-ooi". "ui" does not sound the same way as "way".

Come to think of it, his last name would have a better effect. "Wu", i.e. "woo" (who).

Re:get your pronounciation right

[some guy I know]

It's pronounced as "h-ooi".

What a bunch of hooey.

no it doesn't...

[YesIAmAScript]

20W in use? Give me a break.

Let's say I'm running at 1W (max for 1800/1900, half max for 850/900). I'm transmitting 1/8th of the time (due to TDMA slotting).

Thus I would use 1/8Wh per hour just to transmit. My phone has a 3Wh battery (800mAh @ 3.8V). So I would have a talk time of 24h, if my phone didn't use power for anything else at all. It does, so the talk time on my phone is 8H.

Now, let's try out your version. I'm using 22W when transmitting, 1/8th of the time. So I'm using 2.8Wh per hour. So, if my phone did nothing else, I would get just over 1 hour talk time.

Except my phone is rated at 8 hours, and tests show 9.

This would be impossible if you were correct.

The way a PLL actually works, yes, a small amount of circuitry in the PLL runs at many times the actual output frequency. But all the circuitry it is designed to drive, which is attached to the output of the PLL runs only at the actual frequency.

In the system I use, the entire power consumed by a PLL is 0.4mW. If they increased the efficiency infinite-fold due to lowering clock rates inside the PLL, it would take 0mW, and the resulting reduction in power used would still be insignificant, because the rate the circuitry the PLL is driving would still be running at the same speed and thus using the same amount of power.

Basically, it appears to completely fail to understand what a PLL is and why it is different from clock-skipping.

Finally, an excuse to drive fast

[jdbartlett]

Hey, I'd like to stick that wind turbine charger on my car roof!

Re:Thats interesting and all

[Anonymous Coward]

I'm sure your Brother would be happy to hear about your heroing ordeal and how you barely escaped losing karma.

You're the real victim, not him.

division by 3

[Anonymous Coward]

"The new chip uses five transistors and can perform divisions by 3 instead of only 2 by previous circuits,"

Does this mean it operates on trinary logic instead of binary?

(In some of R A Heinleins stories the computers were trinary)

If i binary digit is called a bit, what is a trinary digit called?

Re:Not(?) A Big Deal

[thestuckmud]

the problem is, even in "standby" the phone does a lot of transmitting, and that transmitting is still a power hog.

I'm having a tough time trying to understand what you mean by "a lot".

My GSM phone transmits short pulses (less than 1us) at irregular intervals. The mean time betwen pulses looks to be roughly two minutes, though my sample is admittedly small. Thus the duty cycle is less than 10E-8, which is only a little in my book.

So the question is whether transmit power is on the order of 100,000,000 times greater than the phone's quiescent power draw. Somehow I doubt it.

Anyway, thanks for giving me an excuse to pull the oscilloscope out of the closet. It was getting lonely.

But what I really want to know...

[Joebert]

How many minutes is this going to add to my battery life ?

No matter what the answer(s) to that question, we all know our phones are still going to die during our most important calls right ?

This is all incorrect. PR & media idiocy as us

[3flp]

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.

[/rant]

Ten times less power ???

[The Famous Druid]

Does this mean it actually supplies enough power to run 9 regular chips?

Can I buy a thousand of these new chips and use them to power my electric car?

Re: usb to 9v battery charger

[AaronLawrence]

Seems to me that a 9V alkaline battery is going to have quite a bit less power than your typical cellphone Lithium-Ion battery....

Re:Thats interesting and all

[Anonymous Coward]

"....and thus is on topic."

And also completely wrong.

So?

[Wellington Grey]

It always happens when you need it the most: the battery of your cellphone just died. But now, researchers of the University of Rochester have developed a wireless chip that needs ten times less power than current designs.

Now I'll just recharge my phone ten times less often and it will still die when I need it most.

-Grey

A Trinary Digit

[Anonymous Coward]

A TIT

Now do you feel better?

(hehehe he said TIT hehehe)

0, 1, 2, 10, 11, 12, 13, 20......

Re:A Trinary Digit

[Linker3000]

8 tits in a tyte?

2 killertits is known as a Pandora

2 Megatits is known as a Morgan

Re:Not(?) A Big Deal

[green1]

the answer is that it depends on a bunch of factors, (this is also why your battery life varies even when you use the phone the same way all the time) the phone will periodically contact the tower to let the tower know that it's there, depending on how strong a signal there is to the tower the phone will decide on how strong a signal is needed to reach it, if you are moving and switching between towers the phone will transmit more frequently so as to introduce itself to each new cell site. if the phone can't get a signal at all it will try transmitting on each of it's modes and at full power in an attempt to contact a cell site (this is the one that takes the most power) on my phone if I'm in the city it will last almost a week of regular usage, however if I take it fully charged in to an area with weak analog signal combined with areas of no signal at all, the phone's battery will be completely dead overnight (or less) and I can tell you that it isn't the reciever that kills the battery so quickly when there's a weak signal, it's the transmitter attempting to contact a cell site.

The article is nonsensical.

[viking2000]

From the article:

The new circuitry topology allows the ILFD to divide by three as well as two.

This tiny change has huge ramifications. A circuit design that can divide by two or three can, for instance, divide 9,999 clock pulses by two, and the 10,000th by 3, giving an average of 2.0001, which could be the frequency at which the cell phone is trying to communicate. Should the phone need to communicate at 2.0002 gigahertz, the ILFD could divide 9,998 clock pulses by two, and the 9,999th and 10,000th by three, yielding an average of 2.0002. By varying how many clock pulses are divided by two or by three, any frequency can be selected, making the power-saving ILFD method viable for the first time.

What does this actually mean? To me it sounds like the writer has no clue as to what they are writing about.

Can somebody please correct me here?

From the above, divide by 3 has little value. Divide by 4 would do just the same. Example: If you can vary how many clock pulses are divided by 2 or 4 (i.e. 2x2), you can get any frequency you want. There is no need for divide by 3.

Divide by 3, however is useful in an oscillator for a totally different reason:

If you can only divide by 2, then your frequency choices are 2,4,8,16 etc, while adding 3 as a factor gives you 2,3,4,6,8,9,10 etc.

This is outlined in detailed in a 4 year old article here:

p. 23: A wide band Modulo-3 ILFD

It states that in inverter based amplifier gives low power.

Hui's chip is described here. (By Hui)

Please give me feedback on this.

Re:The article is nonsensical.

[Anonymous Coward]

How can you divide by 10 if you can divide by 2 and 3?

why can't cellphones standby as long as pagers?

[albeit]

Pager batteries last a long time because they just listen for a page and don't continuously communicate with the network. Why can't cellphone work the same way when not in use? I guess the answer is that cellphones won't work as smoothly or as transparently as a phone has too because there will be some delay in knowing that the phone can even ring (it might be off altogether). It sure would be more efficient if there were at least a mode like that you could switch into. Of course, the type of network is completely different (probably cost big bux) and you can receive pages in a lot of places where you can't get a cell call.

Re:why can't cellphones standby as long as pagers?

[dtmos]

Pager batteries last a long time because, while both pagers and cell phones spend most of their time asleep (neither transmitting nor receiving), as you suggest the pager can tolerate higher latency than a cell phone. People tolerate page latency of 30 seconds or more; it's a store-and-forward system. Trying to keep a caller on the line for 30 seconds while a cell phone call is set up (in addition to other inherent network delays) is another thing entirely. Having the luxury of long latency enables low pager system duty cycles, and therefore low average power consumption and long battery life.

It is also true that cellular protocols are far more complex than paging protocols (cf. the GSM spec with, say, POCSAG or FLEX), and the hardware to implement them requires more power consumption when active. Not only is the physical layer more complex (and often at a higher frequency), but there is additional decryption, data deinterleaving, etc. required, too. Phone manufacturers have been largely (if not totally) unable to justify the additional cost of a separate, simple, paging-like receiver in phones to improve their standby time, although a search of the USPTO records will indicate that lots of people have considered the idea.

Finally, it is also true that the need to include a relatively high-powered transmitter in the phone requires some compromises in standby power consumption. For example, to get high efficiency from a transmitter power amplifier one likes to have a high supply voltage, fed from a source of low output impedance (internal resistance) and high capacity. Ergo, lithium batteries for maximum talk time. However, the receiver has no such requirement; in fact, its power consumption drops with the supply voltage. (This is another reason why pagers ran from a single 1.5V AAA cell.) The cell phone, however, can't operate from separate transmit and receive batteries--I, at least, wouldn't buy one--so the compromise is that the receiver either runs from the high voltage of the lithium battery directly (an unappetizing choice), runs from the low-voltage output of a linear voltage regulator supplied by the battery (only slightly more appetizing, since the system efficiency is still poor), or runs from the low-voltage output of a switching voltage regulator (possibly the best choice, if the electrical noise can be tolerated, even though the regulator still adds power consumption). Or some combination of the above, any of which is still less power-efficient than running from a low-voltage source in the first place.

Re:why can't cellphones standby as long as pagers?

[albeit]

Excellent thanks. Hadn't thought about the battery considerations. I guess one could always use a second battery, but again that adds expense.

Re:Thats interesting and all

[Hank the Lion]

The red cones in your eye react more slowly than the other color receptors. Therefore when you are looking at the red led, which is a pure red light surrounded by darkness (not common in nature btw) what you are actually seeing is the vibration due to the crunch momentarily after they happen.
Sorry, no. Bruce Perens (above) gave the correct explanation: stroboscope effect, caused by the rapid blinking of the LEDs.
The same can happen with any other colour.
If you look at an (in my case green) oscilloscope from a distance, when the timebase is at a rather low frequency (say: 1 ms/div, or 100 sweeps/sec) and you clap your teeth together, you see a waveform on the scope. The further you are away, the better it looks.
I used this to confuse interns at our company, saying that I made a sound detector specifically for clapping teeth, that was more sensitive with increasing distance.

Where is the -1:Clueless moderation option when you need it?

Perpetuating the propagation loss myth

[dtmos]

I'm considering the devotion of the rest of my professional career to the eradication of the "propagation loss increases with frequency" myth.

Repeat after me:

Propagation loss does not increase with frequency!
Propagation loss does not increase with frequency!
Propagation loss does not increase with frequency!

Think about it: If the propagation loss of an electromagnetic wave increased in proportion to its frequency, there would be so much so much attenuation at the THz frequency of light that we'd never see sunlight--or stars. Propagation loss is independent of frequency, except for scattering due to molecular and atomic resonances that are insignificant at the frequencies we're discussing. (There are also changes in scattering behavior that become relevant in indoor applications, like propagation around corners.)

What is dependent on frequency, however, is the performance of the antennas we use to transmit and receive electromagnetic waves. Antennas can be characterized by a parameter called effective area. Returning to the sunlight example, recognize that the output power of a solar panel is proportional to its physical area; the larger this area, the greater the fraction of the incident power transmitted by the sun is received by the solar panel and converted to available output power. Receiving antennas, and antennas in general (even wire antennas), have an effective area; it's the area required to produce the measured output power, based on the density of transmitted power (watts/unit area) at the location of the receiving antenna.

Antennas can also be characterized by their gain, a function of their directivity and efficiency.

Interestingly, based on these two parameters any given antenna can be placed into one of two categories: There are constant-area antennas, the effective area of which is constant with frequency, and constant-gain antennas, the gain of which is constant with frequency. Constant-area antennas have gain that increases with frequency; constant-gain antennas have effective area that decreases with frequency.

The source of the myth is that most portable consumer wireless products use constant-gain antennas, usually some variant of a dipole. While the gain of a resonant dipole is constant with frequency, as the frequency goes up its physical length, and therefore its effective area, goes down. 2.4 GHz dipoles are physically smaller than 900 MHz dipoles. They therefore have less effective area, and recover less power from the incident wave. It seems like the path loss at 2.4 GHz is greater, but it's really just a result of the antenna choice in the product design. If consumer products used constant-area antennas, like a parabolic dish of fixed physical dimensions, exactly the opposite result would be found: Since constant-area antennas have gain that increases with frequency, the recovered power at 2.4 GHz would be greater than that at 900 MHz, and we could start a myth that propagation loss decreases with frequency.

Interestingly enough, if the transmitter has a constant-gain antenna and the receiver has a constant-area antenna (or vice-versa), the recovered power at the receiving antenna terminals would be independent of frequency (i.e., constant), and we could avoid the generation of propagation loss myths entirely.

Re:Perpetuating the propagation loss myth

[Anonymous Coward]

free space loss

"Propagation loss does not increase with frequency!"

Since you mention that, I'd like to ask what you think about free space loss equations.

Link there says: "Free space power loss is proportional to the square of the distance between the transmitter and receiver and also proportional to the square of the frequency of the radio signal." So far I haven't found a good explanation why frequency comes into this at all.

Maybe we can still see stars because they emit jillions (technical term) of watts of energy?

If anything I thought this "propagation loss increases with frequency" myth had something to do with the free space loss equation, but what the hell do I know.

What are your thoughts on this matter? I'm not an EE or anything of the sort so go easy.

Re:Perpetuating the propagation loss myth

[dtmos]

I think equations like this are how the myth got started in the first place. The equation does not describe what it claims to describe ("free-space loss"), because it makes the (unstated) assumption that constant-gain antennas are used. It then combines the free-space loss (the "proportional to the square of the distance" term, caused by the increasing area of the sphere enclosing the transmitter as one moves away from it) with the antenna term (the "proportional to the square of the frequency" term), to get some sort of combination that in fact can be used for communication link analysis if you're using constant-gain antennas. Defining some terms (trust me, I'll be gentile),

Umax = maximum radiation intensity (i.e., the maximum watts/unit area of a sphere enclosing a (transmitting) antenna in some preferred direction).

Uavg = average radiation intensity (i.e., the average watts/unit area of a sphere enclosing a (transmitting) antenna) = 4pi/(power radiated).

D = directivity = Umax/Uavg.

G = antenna gain = D (for antennas that are 100% efficient, a reasonable approximation for most cases with which we're concerned here).

A = effective area = (power produced at the antenna terminals)/(power density of the incident received wave); e.g., watts/(watts/square meter) = square meters.

wavelength = (speed of light)/(frequency); e.g., wavelength in meters = 300/(frequency in MHz).

You may have notice a gear-shift in moving from the definition of directivity to that of effective area--I defined directivity using a transmitting antenna, but effective area in terms of a receiving antenna. Fortunately, the terms are reciprocal; both terms apply equally well to both transmitting and receiving antennas.

The crux of the matter, and the source of the frequency term in the "free-space" equation, is the next equation. The directivity D (and therefore the gain G, under our assumption of 100% efficiency) of any antenna is related to its effective area A and the wavelength of the incoming wave:

D = G = A*4pi/(wavelength)^2 = A*4pi*(frequency)^2/(speed of light)^2.

If we assume that the antenna gain G is constant then, as the wavelength (i.e., frequency) changes, its effective area must, too. The gain of a dipole is constant at 2.14 dB, relative to an isotropic source; its effective area, however, is (30/73pi)*(wavelength)^2, or about 0.13(wavelength)^2. However, if we assume that the antenna is a different type, with constant area A, then as the wavelength changes its gain must change. Either assumption is valid, depending on the type of antenna we are employing. The confusion arises when people use the Wikipedia "free-space" equation to model path loss, then want to experiment with different antenna types. They don't realize that they're modeling their antennas as part of the "free-space" path loss. Wild errors result, for exampe, if you use Wikipedia's equation with parabolic dish antennas, like you often do in microwave point-to-point systems.

I guess a more subtle and pervasive problem arises when the equation gives people the idea that there's something inherently "bad" about propagation at higher frequencies, and that we should therefore all fight for operation at lower frequencies. Which, I guess, is what so motivates my rant.

In summary, you're right--frequency shouldn't come into this at all, and the second term of the equation in Wikipedia should be removed.

p.s.: And I thought my starlight/sunlight explanation was bulletproof. Maybe I should use flashlights? Lighning bugs?

Re:Perpetuating the propagation loss myth

[Anonymous Coward]

I appreciate your response.

Hearing the myth caused me concern that somehow, perhaps magically, EM radiation was being robbed of its power more and more at higher frequencies as it travelled through a vacuum with no explanation other than "the equation says so."

Good rant.

THE PARENT IS COMPLETELY BOGUS!

[Anonymous Coward]

The parent is completely wrong about how frequencies are controlled in communication circuits, or any other circuits for that matter.

From the parent: "This is important because traditional digital circuits which communicate with each other on specific frequencies, do so by running a clock speed of at least 10 times the communication frequency,"

No. Traditional digital circuits use a phase locked loop. It runs asyncronously. It isn't clocked. The highest frequency involved with any digital circuitry would be the counter which would have to run at the transmitter frequency. Using a frequency divider it is possible to get around that problem too.

Ten times the communication frequency would be 20 GHz. How many chips are you aware of that run at 20 GHz. Modding the parent +5 just shows that people will believe any kind of plausible sounding bs. Give me a break folks. This is just clueless.

http://www.uoguelph.ca/~antoon/gadgets/pll/pll.htm l

Not to worry.

[dtmos]

The RF signal is typically a sine wave generated by a VCO (voltage-controlled oscillator) that drives the first stage of the divider (prescaler). At the high frequencies used by RF synthesizers, the output pulses of the first stage aren't square, either. They're a sort of a mush; a compromise between the power consumption of your concern and the desire to use CMOS logic for its other low-power features in a highly-integrated system. The first stage of the divider typically draws half or more of the total power, but it is only driven hard enough to enable reliable CMOS operation, not produce square waves. As you go down the divider, the signals gradually move from the sine wave of the input to asymptotically approach a square wave at the output.

The technical term

[dtmos]

Is a antenna which can change direction depending on a signal already there?

The technical term for what you want is retrodirective array.

Re:Thats interesting and all

[owlstead]

Please do not make jokes about cancer like that. Cancer is not in the slightest way funny.

bad heuristic

[penguin-collective]

That heuristic only works for devices that don't emit anything else, and even then it ignores a lot of important factors.

Furthermore, it doesn't tell you whether a component is responsible for high overall power consumption; in order to be responsible for high overall power consumption, a component doesn't need to use a lot of power itself.

Re:bad heuristic

[Bruce Perens]

You mean looking for heat is a bad hueristic for parts that radiate some other energy? Well, if you have really efficient components. Even if RF amplifier transistors are run as switching rather than linear devices, they are not 100% efficient and make some heat. If you run them in their linear region, they are going to spend a lot of time acting like resistors and will make a lot more heat. LEDs warm up a bit, too.

Consider that microprocessors are CMOS digital devices, we're not unused to getting some heat out of them.

I think it's a really simple hueristic that works almost all of the time. I have heard from some less technical folks who think that their "200 watt powered PC speakers" are using 200 watts of AC power all of the time. Explaining the heat thing works really well for folks like that.

Bruce

Re:bad heuristic

[Anonymous Coward]

Components can consume little power and get very hot. Components may stay cool because they are well cooled.

What gets hot really just doesn't tell you all that much about where the power is dissipated, let alone which system components you need to modify for the system to consume less power.

Re:Thats interesting and all

[Briareos]

Please do not make jokes about cancer like that. Cancer is not in the slightest way funny.

I find your lack of tumour really disturbing...

np: Burnt Friedman & Jaki Liebezeit - Fearer (Secret Rhythms 2)

We have the technology!

[mtabini]

The new chip uses five transistors and can perform divisions by 3 instead of only 2

Now, that's what I call a major breakthrough. Watch out for a chip that can do subtraction and addition too, next.

Re:This is all incorrect. PR & media idiocy as

[hankwang]

Slashdot's editorial quality has degraded in the last few years so much that I am thinking about deleting it from my bookmarks.

Calm down... Most people come to slashdot for the comments. The articles themselves only serve as a starting point for a discussion, which is often valuable since there are always people like you who really know what they're talking about.

Do you want LONGER CELL phone LIFE?

[Anonymous Coward]

If you buy now you can make your CELL LAST LONGER and divied your RF BY UP TO THREE TIMES AS MUCH!!! Works just like an INJECTION! Buy now at our website!

Nonsense!

[gweihir]

Phones do not communicate with phones! Phones communicate with base-stations. If this adjustment was really a power issue, then it could be done in tha base-station. However it is not. The power issue is the sending power. If you put out 2 Watt of RF, then you have to drain at least 2 Watt from your battery. There is no way around that in this universe.

Personal guess: Sloppy journalism and a marketing depatment working hand in hand. This is non-news and none of the stated benefits is even possible.

Bad slashdot! Sit in the corner slashdot!

spanish

[jheath314]

I for Juan welcome...

Where are the stories titled

[WML MUNSON]

New Battery Promises Longer Battery Life?

nit pick

[Anonymous Coward]

ahem, that's Library ofs Congress

works ok over short range.

[petermgreen]

the trouble is especailly with omnidirectional antennas its fantasically inefficiant and that efficiancy drops off with the SQUARE of the distance.

and you need enough power to get the signal back. so your equation would be something like

new transmit power at base station= old transmit power at source station divided by old receive power at phone multiplied by old transmit power at phone = massive.

and thats not accounting for the losses inherent in going from radio to electricity and back.

its feasible for very short range simple devices (e.g. rfid) but totally unfeasible for something like cellphones.

Re:Thats interesting and all

[afroborg]

You just made that up, and guess what - it's 100% wrong.
The correct answer (strobe effect) is given by another poster above.

Re:Thats interesting and all

[ltbarcly]

That's the answer that was told to me. I'm sorry I upset you so much.

Re:This is all incorrect. PR & media idiocy as

[jafac]

Slashdot's editorial quality has degraded in the last few years so much that I am thinking about deleting it from my bookmarks.

Take it from an old-timer. Slashdot's editorial quality has remained pretty much consistent for about its entire existence.

Who needs batteries in the Future?!

[RabidTrucker]

That's a great advance. I applaud the hard work. I guess
my engine in the nanosize wouldn't work then >
http://www.newpath4.com/millenialdawnpowerandlight secure21.htm .

Sounds like an application of ternary computing

[Stultsinator]

There was an excellent thread here some time ago.

The Sun seems to be having some success.

[Damek]

Just sayin'.

But I suppose we'd need to violate plant patents to be able to interface with its system...

Re:The Sun seems to be having some success.

[Com2Kid]

Not really.

You compare how much energy the sun is putting out on its surface, to how much is getting to us.

What the inverse square law doesn't kill, our planets magnetic field and ozone deplete.

Actually a ton of energy is just out of our reach as it is direction away from us by the Earth, this is one reason that the satellite based power stations are a decent idea. Collect the energy, convert it over to a form that can be transmitted down to earth, and beam it down in a tightly controlled fashion.

It is not economically feasible yet because we have not depleted other sources of energy from the planet. Heartless, but that is the way it works I'm afraid.