However, as an example of what you talk about, we have had a flight or two where we are flying and the pilot asks us "OK, who has their phone on?" because he can pick up the interference (I'm not sure exactly, but I think it was from GSM phones).
Any phone using TDMA is just about the worst case for interference because the access method itself is effectively low frequency modulated AM which is easily detected (in the electronics engineering sense) by any non-linear device. The usual culprit oddly enough is the output stage of an audio amplifier through the speaker leads but almost any interface is susceptible.
This is also why CBs and AM modulated HAM transmitters cause problems.
I dont understand why attitude indicators would fail to function with clogged pitot tubes, (and even statics). Also you can't tell airspeed, but from gps ground speed you should still be able to tell roughly how fast you are going. So with ground speed and artificial horizon it should be still flyable. Not easy but flyable.
The flight envelope in this case apparently only has about 30 knots of margin so ground speed is not sufficient.
The procedure in this case is to set the engine throttle to a specific power and maintain attitude for a given altitude which will yield an acceptable airspeed but for whatever reason that did not happen.
I can think of two to uses off the top of my head. The first is for really fast frequency hopping radios. The rate at which they can hop from one to the next has got to be in some measure limited to how accurate the clock they use is.
Frequency hopping spread spectrum, direct sequence spread spectrum, and TDMA systems can phase lock their local oscillators together so absolute accuracy is not required. Performance is only limited by local oscillator phase noise. An atomic oscillator would help with synchronization from a cold start but the standby power cost is pretty high.
Atomic oscillators do not particularly have better phase noise performance than crystal or especially YIG oscillators. Crystal oscillators are often phased locked to a GPS or atomic source allowing the best characteristics of both.
A microwave typically uses a frequency of 2.45 GHz, which is in the WiFi band. If her oven leaks RF power outside, it will indeed kill all the WiFi channels. A WiFi AP transmits 200 mW, a microwave can use 750 to 900 W. Of course this energy is supposed to stay inside the oven, but if the oven has a defect or is not well shielded and even a small part of this leaks it will blind all WiFi receivers around for sure.
Part of the problem is that integrated wifi receivers have atrocious out-of-channel performance. Direct conversion receivers are not known for high dynamic range and the low price points targeted do not support good filter implementations anyway.
Anybody with a tiny bit of knowledge about radio wave propagation, and a portable device with a wifi signal strength meter, could track it down to within a small area in a few minutes. I can't imagine why you think broadcasting high power radio signals could ever be even remotely difficult to trace.
Well, he might have experience doing amateur radio transmitter hunting.
I have lured people to locations 10s of miles away (and across some 5000 foot mountains) from the actual transmitter before and at least a couple times managed to broadcast a clear signal where nobody was able to find it at all without help. Once with a very very good low gain directional antenna designed for low side-lobes and another time by gamma-matching a high voltage power transmission tower.
One thing i have learned in my life: If you are the smaller customer group affecting the larger customer group in any way, you lose if your interests collide. Never rely on a technical solution under these circumstances, and if you do, reserve the resources to dedicate duplicate resources in some way.
Sony, other unwieldy companies, and their large customer groups may have learned a lesson as well . . . bwhahahahaha . . . who am I kidding?
One thing I have learned in my life: If you are the larger customer group affecting the technically proficient smaller customer group in any way, you lose when your interests collide. Never rely on a large company's technical proficiency under these circumstances, and if you do, reserve the resources to dedicate duplicate entertainment in some way.
1. I'm genuinely curious as to what types (or brands) of devices cause such anomalies.
These days legacy hardware would be the largest source of problems for switched ethernet implementations except for consumer grade switches.
2. Don't use a crappy switch! 3. Don't use a crappy switch!
I have seen quite a few embedded switches with this problem in which case replacement is difficult.
In theory a good switch with false collision flow control should be a good hub replacement but for some reason they do not always work out. In some control systems the added switch latency uncertainty is a problem. Hubs in this case have the advantage that the sender knows exactly when the receiver gets the packet barring data errors.
Yeah the 50 is a little better. Still isn't a pity that 2 decades later you are talking about slightly better keys?
I have a couple of good soft key calculators but the HP models after the HP-48g(x) and before the HP-50g had a lot of poor reviews and not just because of the keyboards.
One other thing I really liked about the HP-50g is the user replaceable coin cell memory backup. It reminds me of my Yaesu FT-530 radio.
My HP-48g was starting to get a little flaky but I replaced it with a HP-50g which so far has been better in all respects. It uses 4xAAA instead of 3xAAA which is more convenient, the keys work well, and the display is better.
The earlier HP-48 replacements either had soft keys or non-rectilinear layouts so I avoided them.
The Core i5-2515E and the i7-2715QE, but I dunno re: mobo compatibility. Those are the only non-xeon Intel cpus which support ECC insofar as I know (using wiki as a reference).
I have read various discussions saying that ECC support is somehow actually tied into the chipset even though Intel's memory controller is now on the CPU but of course uncertainty just makes it more difficult to justify buying Intel anyway.
AMD ECC support tends to be more a function of the BIOS, since all their cpus now support ECC. ASUS has always had good BIOSes so it is no surprise there. Gigabyte will be a bit more spotty, though I think the GA-MA770T-UD3P specifically supports it. The more popular 880GMA-UD2H's can take ECC sticks but it is unclear whether the mobo turns on the ECC and the BIOS doesn't have ECC options.
I have read a couple of tutorials for enabling ECC support under Linux and BSD where BIOS support was not provided assuming that the hardware was capable of it. As far as determining whether ECC support exists for the general case, I ended up going through the manuals for prospective motherboards to check what the BIOS options were. At least back when I built my Phenom II, all Asus motherboards supported it, Gigabyte motherboards without embedded graphics supported it, and no other manufacturers did.
Consumer boxes these days support 16-32G of ram (and all AMD mobos and all high-end Intel consumer mobos support ECC).
Which Intel based consumer boards support ECC? Or do you mean with an appropriate Xeon processor?
Not all AMD motherboards have ECC support but in theory they could have. At least when I was buying, Gigabyte did not support ECC on motherboards with embedded graphics for some reason whereas Asus supported ECC on all AMD motherboards or at least those with AMD chipsets.
My current system is an old AM2+ Phenom II 940 because at the time the only Intel choices which supported ECC were deprecated Core2 chipsets or very expensive workstation/server boards that required FB-RAM. The equivalent Intel systems ended up being about 2 to 3 times more expensive (cpu, motherboard, and RAM) and were actually significantly slower because of low CPU clock speeds at that price.
If compromised data includes PIN numbers for debit cards, or CVV2 data for credit cards, which merchants aren't supposed to store at all, VISA sends in a Qualified Security Assessor.
How do recurring payments work without PINs or CVV2s? Is there some type of continuing authorization which assumes that the price does not change?
Right now the aging Phenom II doesn't even compete well against Intel's 200$ processors, the X6 is really the only high-end chip worth buying today.
You are right about that but it competes very well against Intel's much more expensive Xeons where suddenly the motherboard plus CPU plus RAM is 3 to 4 times more expensive if you go with Intel.
Basic EE stuff: Z = 1/(jwC). And how do we generate the radio frequency? With a VCO that invariably involves big capacitors (big for an IC, at any rate). Those VCOs typically end up drawing at least 50-60% of your operating current.
The capacitor in a VCO is in a tuned circuit so the circulating power can indeed be high but the actual power draw is much much lower. If this was not the case, then the tuned circuit Q would be low leading to high oscillator noise.
Close in phase noise is actually a significant limitation leading to relatively high VCO transistor bias current but compared to the power amplifiers where linearity is a limitation it is still insignificant.
RF power amplifier efficiency rarely gets above 30% and that is for a device which is already drawing a lot of power anyway. The biggest improvements there involve better but more complicated designs using things like predistortion or Doherty amplifier design to yield better linearity for a given efficiency.
Fun idea but the designers would be stupid to have not thought of this: optocouplers, current-limiting resistors, and ESD-protection structures are routinely put on device inputs/outputs intended for consumer usage, especially in industrial settings where the devices are expensive and expected to be used by inexperienced operators. I design stuff like this at work, and the chips and systems we make can handle thousand-volt spikes and have car batteries shorted across the leads: they don't draw enough current to get hurt and they have high(ish) voltage diodes to protect them from getting zapped through casual handling. If you can jam several kilovolts down that data line then you can probably do some damage, but then you're carrying something somewhat dangerous to you and any accessory you plug it into as well.
ESD is designed to protect against normal static discharges though. Gas discharge tubes would survive but semiconductor based protection tends to fail in a short which would render the device inoperable anyway. Resistors usually fail open and capacitors usually fail closed also causing a device failure at least as far as the I/O port goes. I have blown out RF receivers before (without even a direct connection) where either the failure was a shorted ESD protection diode which protected the first RF stage or where an ESD protection diode was not used the failure was the first RF stage instead. The input bandpass filter was not a factor since these were in-band overloads.
I guess the best protection designs I have done all involved ESD protection followed by a semiconductor cascode which could handle continuous overloads and included fold-back current limiting. They would survive at least 10 times the machine or human ESD model as well as direct connection to a 120/240/277 volt AC power circuit but were not low level high speed interfaces which usually just have shunt ESD protection and mild overload protection if any. I am certain that a small capacitive discharge circuit would easily destroy most consumer and industrial low level interface designs. The protection is intended against accidental static discharge and not against deliberate malice.
Oh, and there's the part about how they did get generators rushed to the site, but the electrical connections didn't match up so they couldn't use them. I'm still not sure that's been reported right, because what the fuck?
It did not help that the switching rooms were submerged and filled with water.
So first, any normal business practice becomes patentable if you add the words "on a computer" to it.
Sure. Just like how substituting a transistor for a tube in a circuit allowed the circuit to be patented again. The cathode follower became the emitter follower, the common grid became the common base, and the common cathode became the common emitter.
* Warning: This post contains sarcasm which may cause cancer, birth defects, or reproductive harm in California. *
There's also less need - the main reason I ever went delving in a Mac (apart from memory and HD upgrades) was to fit ethernet cards - these days, you'll find at least one ethernet port (probably plus WiFi) built in to any half-decent board, and anything else can be fitted via USB.
I have actually found more reason to add expansion cards in the past couple of years because USB serial converters fail with some serial devices (this seems to be getting worse) and what do you do for your second ethernet port? Or third even. One for the shared WAN connection, one for local high speed file sharing (not needed so much now with ubiquitus gigabit ethernet although with faster file server hardware you might want to bridge some ports), and one for configuring other devices which are living on weird subnets.
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Any phone using TDMA is just about the worst case for interference because the access method itself is effectively low frequency modulated AM which is easily detected (in the electronics engineering sense) by any non-linear device. The usual culprit oddly enough is the output stage of an audio amplifier through the speaker leads but almost any interface is susceptible.
This is also why CBs and AM modulated HAM transmitters cause problems.
The flight envelope in this case apparently only has about 30 knots of margin so ground speed is not sufficient.
The procedure in this case is to set the engine throttle to a specific power and maintain attitude for a given altitude which will yield an acceptable airspeed but for whatever reason that did not happen.
The lessor evil is still evil.
ATF and the US Marshals are the ones with the guns. The FBI prefers fire.
Frequency hopping spread spectrum, direct sequence spread spectrum, and TDMA systems can phase lock their local oscillators together so absolute accuracy is not required. Performance is only limited by local oscillator phase noise. An atomic oscillator would help with synchronization from a cold start but the standby power cost is pretty high.
Atomic oscillators do not particularly have better phase noise performance than crystal or especially YIG oscillators. Crystal oscillators are often phased locked to a GPS or atomic source allowing the best characteristics of both.
Part of the problem is that integrated wifi receivers have atrocious out-of-channel performance. Direct conversion receivers are not known for high dynamic range and the low price points targeted do not support good filter implementations anyway.
Well, he might have experience doing amateur radio transmitter hunting.
I have lured people to locations 10s of miles away (and across some 5000 foot mountains) from the actual transmitter before and at least a couple times managed to broadcast a clear signal where nobody was able to find it at all without help. Once with a very very good low gain directional antenna designed for low side-lobes and another time by gamma-matching a high voltage power transmission tower.
Sony, other unwieldy companies, and their large customer groups may have learned a lesson as well . . . bwhahahahaha . . . who am I kidding?
One thing I have learned in my life: If you are the larger customer group affecting the technically proficient smaller customer group in any way, you lose when your interests collide. Never rely on a large company's technical proficiency under these circumstances, and if you do, reserve the resources to dedicate duplicate entertainment in some way.
These days legacy hardware would be the largest source of problems for switched ethernet implementations except for consumer grade switches.
I have seen quite a few embedded switches with this problem in which case replacement is difficult.
In theory a good switch with false collision flow control should be a good hub replacement but for some reason they do not always work out. In some control systems the added switch latency uncertainty is a problem. Hubs in this case have the advantage that the sender knows exactly when the receiver gets the packet barring data errors.
Yeah the 50 is a little better. Still isn't a pity that 2 decades later you are talking about slightly better keys?
I have a couple of good soft key calculators but the HP models after the HP-48g(x) and before the HP-50g had a lot of poor reviews and not just because of the keyboards.
One other thing I really liked about the HP-50g is the user replaceable coin cell memory backup. It reminds me of my Yaesu FT-530 radio.
I have read about this in various James P. Hogan novels. It always turns out bad . . . for us.
My HP-48g was starting to get a little flaky but I replaced it with a HP-50g which so far has been better in all respects. It uses 4xAAA instead of 3xAAA which is more convenient, the keys work well, and the display is better.
The earlier HP-48 replacements either had soft keys or non-rectilinear layouts so I avoided them.
Off hand, I can think of three reasons to use a hub instead of a switch:
1. A hub can be more reliable if you have devices or switches which do not implement flow control correctly or at all.
2. A hub may work better in applications where it is better to delay sending a packet if it would be otherwise lost because of congestion anyway.
3. Ethernet switches with excessive packed buffering can cause problems and this is not often (ever?) adjustable.
I have read various discussions saying that ECC support is somehow actually tied into the chipset even though Intel's memory controller is now on the CPU but of course uncertainty just makes it more difficult to justify buying Intel anyway.
I have read a couple of tutorials for enabling ECC support under Linux and BSD where BIOS support was not provided assuming that the hardware was capable of it. As far as determining whether ECC support exists for the general case, I ended up going through the manuals for prospective motherboards to check what the BIOS options were. At least back when I built my Phenom II, all Asus motherboards supported it, Gigabyte motherboards without embedded graphics supported it, and no other manufacturers did.
Which Intel based consumer boards support ECC? Or do you mean with an appropriate Xeon processor?
Not all AMD motherboards have ECC support but in theory they could have. At least when I was buying, Gigabyte did not support ECC on motherboards with embedded graphics for some reason whereas Asus supported ECC on all AMD motherboards or at least those with AMD chipsets.
My current system is an old AM2+ Phenom II 940 because at the time the only Intel choices which supported ECC were deprecated Core2 chipsets or very expensive workstation/server boards that required FB-RAM. The equivalent Intel systems ended up being about 2 to 3 times more expensive (cpu, motherboard, and RAM) and were actually significantly slower because of low CPU clock speeds at that price.
How do recurring payments work without PINs or CVV2s? Is there some type of continuing authorization which assumes that the price does not change?
You are right about that but it competes very well against Intel's much more expensive Xeons where suddenly the motherboard plus CPU plus RAM is 3 to 4 times more expensive if you go with Intel.
The capacitor in a VCO is in a tuned circuit so the circulating power can indeed be high but the actual power draw is much much lower. If this was not the case, then the tuned circuit Q would be low leading to high oscillator noise.
Close in phase noise is actually a significant limitation leading to relatively high VCO transistor bias current but compared to the power amplifiers where linearity is a limitation it is still insignificant.
RF power amplifier efficiency rarely gets above 30% and that is for a device which is already drawing a lot of power anyway. The biggest improvements there involve better but more complicated designs using things like predistortion or Doherty amplifier design to yield better linearity for a given efficiency.
ESD is designed to protect against normal static discharges though. Gas discharge tubes would survive but semiconductor based protection tends to fail in a short which would render the device inoperable anyway. Resistors usually fail open and capacitors usually fail closed also causing a device failure at least as far as the I/O port goes. I have blown out RF receivers before (without even a direct connection) where either the failure was a shorted ESD protection diode which protected the first RF stage or where an ESD protection diode was not used the failure was the first RF stage instead. The input bandpass filter was not a factor since these were in-band overloads.
I guess the best protection designs I have done all involved ESD protection followed by a semiconductor cascode which could handle continuous overloads and included fold-back current limiting. They would survive at least 10 times the machine or human ESD model as well as direct connection to a 120/240/277 volt AC power circuit but were not low level high speed interfaces which usually just have shunt ESD protection and mild overload protection if any. I am certain that a small capacitive discharge circuit would easily destroy most consumer and industrial low level interface designs. The protection is intended against accidental static discharge and not against deliberate malice.
Are these the same docks which have to survive the tsunami which took everything else down?
It did not help that the switching rooms were submerged and filled with water.
The fuel tanks were washed away and the switching rooms were under water.
Garry: The generator's gone.
MacReady: Any way we can we fix it?
Garry: It's "gone", MacReady.
Sure. Just like how substituting a transistor for a tube in a circuit allowed the circuit to be patented again. The cathode follower became the emitter follower, the common grid became the common base, and the common cathode became the common emitter.
* Warning: This post contains sarcasm which may cause cancer, birth defects, or reproductive harm in California. *
I have actually found more reason to add expansion cards in the past couple of years because USB serial converters fail with some serial devices (this seems to be getting worse) and what do you do for your second ethernet port? Or third even. One for the shared WAN connection, one for local high speed file sharing (not needed so much now with ubiquitus gigabit ethernet although with faster file server hardware you might want to bridge some ports), and one for configuring other devices which are living on weird subnets.
It allows me to see more stack entries. Err, wait . . . TI calculators have a stack, right?