but avionics are _very_ well shielded, so they chance of devices actually interfering directly with them is extremely remote.

what is more likely is that the can jam anything receiving a signal, e.g. gps receivers and radios.

I'm reminded of the fact that komodo dragons have a strong anti-bacterial chemical due to the biome in their mouths which is used to infect prey so they'll get sick and die.

obviously a specialized case.

as deadly as bacterial infections have been to humans throughout history, it's somewhat confusing that we don't have a more potent biochemical arsenal.

not too mention SML which is a really nice language to use for large projects.

it's amazing how pervasive C still is.

my wife was in that category . we eat well, she walked regularly and could not lose weight.

stopped dairy, especially milk and lost 20 pounds in 6 mos. I'm still amazed at how fast she lost the weight.

She hated it too, because she loved milk.

there's also the idea of removing heat from the power supply.

a higher efficiency box is higher efficiency because there's less resistance. this tends to mean the components have to be oversized and therefore run cooler.

this _should_ improve the long term reliability of your power supply.

otherwise why are the police afraid of a woman with cell phones ?

And make no mistake, they were _afraid_. Either that or they're sadistic bastards who enjoy tasering people, which is entirely possible.

I for one do not welcome our para-military police overlords.

they can handle as much as you want - they just get a lot harder to implement because the feedback loop typically has to be 5x the bandwidth of the operating bandwidth to make sure it can compensate for 3rd and 5th order products.

AGC has nothing to do with linear operation of the amplifier (well it does but only to the extent that operating at really low power levels is more linear) . The problem with these modulation schemes with high Peak to average is that they require the amplifier to be "backed-off" in such a way that they are biased for linear operation but they put out only 1/10th the power that the bias condition should be able to support.

so for example a PA biased for 1/2W operation can only be operated at 50-100mW out, making your efficiency something on the order of 10-20%. A class C amplifier for GSM use, for example is pushing 60-65% efficiency.

which wouldn't be a problem except that darn near everything is moving towards OFDM type modulation.

aha - I missed that note. Now it makes more sense. Those sorts of PAs would be close to unusable even with a PD loop.
still requiring a PD loop is still a big problem.

and there's still the issue that you can get these efficiencies with a pure PD loop. This scheme still has the problem that wide bandwidths are going to require a wide bandwidth feedback loop.

  One way to do high efficiency is to do separate phase and amplitude modulation, the so called A-theta modulator. you get your amplitude control by adjusting the PA voltage _continuosly_ and do your phase modulation with an IQ modulator.

For wide bandwidth modulation formats this is a bit of a pain since you need a very wideband, high current, power supply. so they are doing an A/theta modulator but trying to simplify the bias control on the PA to avoid that.

What I'm not clear on is why they are doing this when they have a predistortion loop anyway. a pure predistortion loop should be able to achieve very similar results without any need for the PA bias adjust. you can also do it with 1 PA instead of two.

maybe it simplifies the PD loop substantially, I can't tell yet from the paper, but it trades this off against needing two PAs and PA bias control. And that PA bias control is a bit of a headache two, because you can't just stick a switch in there. The selectable bias levels have to come from a switching power supply which switches between different output voltages. doing this is also non-trivial.

I don't know, looks like somebody's thesis to me. Doesn't look like it's particular practical.

Also, first rule of looking at schemes like this. How much of that power they saved is being used in the more complicated digital circuitry. That's the reason you don't see PD loops in cell phones. It's a wash, you spend so much power analyzing the signal to do PD that you burn up the savings . Now if you have a 10W transmitter, PD makes lots of sense.

with enough advance warning would simply landing a rocket on the asteroid and having it provide a constant thrust be enough to have the asteroid miss ?

at a great distance it would take very little course adjustment which could be provided by a very low thrust.

the obvious complication being if it's tumbling. even then it seems that such a scheme would still work as the rocket could align itself under guidance or using the stars and provide force at the proper time.

not sure why this is never mentioned as an option.

heat causes semiconductor devices to work less well over time. The design must provide for appropriate heat dissipation. A design in which the devices are running at 110 or 120C on a consistent basis will begin to slowly fade. I'm talking about channel temperatures. your box may be "warm" but that could mean that the devices are running hotter than they should for long term reliability.

also a possibility, and my personal favorite. the clock oscillator. poor, even mediocre, clock oscillators have crummy aging characetistics. take that design which is running too hot : the crystals age faster than normal and eventually your device's frequency is too far off. as it begins to drift out, the reception will suffer.

repeat after me: modern electronics for the consumer market are designed for cost. it is expected that you will replace it in 2-3 years. when something lasts you 5 or 6, it's not by design. so if they can save $1 because they don't use the necessary heat sinking or board area to dissipate the heat, and everything is running at 90 or 100C, that's ok. ship it !

send them to the US so the US can pay to imprison them. So you've gotten rid of a "troublemaker" and you don't have to pay to deal with them.

60GHz might travel farther than you think.

an antenna at 60GHz is about 2.5mm, and that's for a basic dipole....

you can easily put multiple antennas on a device, which means you can use beam-forming and get some very tasty antenna gain, maybe on the order of 12 to 15dB.

there are a whole lot of if's attached to that since it depends on a very solid baseband implementation, but theoretically the use of phase array antennas/beam-forming could negate the much higher path loss.

not quite right. N and AC and eventually AD use MIMO which is physically separate transmitters and receivers, i.e. multiple channels.

MIMO doesn't quite get N x (transmitters/receivers) of performance, but it comes pretty close.

AC simply provides for even wider channels than N, i.e. 80 and even 160 MHz channels, but still uses MIMO. It also has a crap load of protocol stuff in it too.

_theoretically_ having multiple receivers would give you a distinct improvement in performance through receiver diversity, but I doubt anybody implements that option.

This all assumes that your client has good radios AND good baseband peformance.

The DSP involved in MIMO is non-trivial and it's very easy to get very sucky performance with a bad implementation. and what do you think is going to happen if somebody f*cks up their baseband ? that's right they're going to try and sell out all of those chips - how the heck are you supposed to know that it's got shitty rate adaptation ? all you see is a cheap client.

the important point is that clients are cheap, and they perform that way.

so in most cases, for home use, you really don't want anything more than a/b/g. if you are doing large file transfers certainly it would be nice to have the higher data rates, but for multimedia streaming over your limited DSL connection there's no point.

a bloom caused by excess nutrients, i.e. pollution, in the water ?

maybe a kind of algae ?

that would be my guess.