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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."
Bruce
Bruce Perens.
Would "ten times less power" be anything like "one tenth as much power"?
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.
liqbase
Bruce
Bruce Perens.
You have brain cancer. Check into a hospital immediately.
Who do you get to be an expert to tell you something's not obvious? The least insightful person you can find? -J Roberts
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).
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."
E pluribus unum
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.
"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*
"I like to lick butts!" by MobileTatsu-NJG (#32700246) (Score:5, Informative)
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.
rajmohan_h@yahoo.com
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!
Need help treating your acne? Come here!
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.
Make a 9volt USB battery charger
p ?pe=CBHJGEGQ_+mobile+phone+wind+up+charger&cid=880
d -powered-phone-charger.html
http://www.hackaday.com/entry/1234000520028239/
Or a WIND UP charger
http://www.edirectory.co.uk/pf/pages/moreinfoa.as
or a WIND TURBINE PHONE CHARGER
http://www.bytesurgery.com/gearedup/2006/02/a-win
Liberty freedom are no1, not dicks in suits.
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?
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!
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.
http://lkml.org/lkml/2005/8/20/95
A while ago, Mythbusters did a "free energy" show. They collected a bunch of plans from "the Internet", built the devices, and tested them.
i sode/episode_06.html).
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/ep
I hate it when I make a joke and I get modded "+5 insightful". Mod the stupid comments "funny", not "insightful", pleas
As you said, it's pure geometry.
http://outcampaign.org/
1: "Hoo" invented this new chip ... Um ... I have to go ... over ... there now ...
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
1: Ok
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]"Argue with idiots, and you become an idiot." -- Paul Graham
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.