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Comment Measured how? (Score 1) 30 30

Halving the noise is not a scientific description. Half the noise power? Half the peak pressure? Half the average pressure? Half the perceived noise?

Half the noise power (3 dB) is so small a difference that an untrained listener couldn't reliably tell the difference between tests performed a day apart.

Comment Re:Passed data with a ton of noise? (Score 1) 351 351

Changing magnetic fields induce voltage along a wire. Two "ground" wires, traversing two different paths through magnetic fields between two pieces of equipment, can result in a current flowing around the loop formed by those two wires. Add more pieces of equipment, and each "ground" can be effectively at a different AC potential. This causes noise in analog signals if the signals are referenced to "ground".

... you use an earth ground, as it's a constant and not relative.

That is a fantasy. There is no one universal earth ground.

Comment Re:Physics and economics don't care (Score 1) 174 174

Most people aren't stupid about light bulbs, including not being stupid enough to buy your conspiracy theory about filament life. Long life incandescent lights are available, giving 2X or 4X life. The problem is that there's an unavoidable tradeoff; long-life bulbs are less efficient, so much less efficient that even including purchase price the long-life bulbs give less light per dollar.

Comment Re:Electric is Evolution. Driverless is Revolution (Score 1) 869 869

In the 1950s and 1960s a typical family car struggled to get 13 mpg on the highway. In the 1970s it got worse, as environmental regulations crippled IC engine performance. Now, a typical family car gets 35 mpg on the highway because the cars are lighter, smaller, and more streamlined, engine technology has caught up with regulations, and tires are better.

This has resulted in the number of US filling stations falling 30% since 1980 and (I'd guess) 50% since 1950. Also, unattended filling stations reduces the number of stations needed. I'd expect the number continue to fall with or without electric cars.

Comment Re:AYFKM? (Score 1) 869 869

Torque in most electric motors is maximum at stall, when it's producing no power. Maximum torque in IC engines is often at about 70% of the redline, just below the maximum power point. EVs should be good at laying rubber off the line, but 0-60 times and maximum horsepower are more important.

Comment Re:everything old is new again? (Score 1) 90 90

In the vicinity of the 0.35 micron node, GaAs starts to lose its speed advantage over silicon in digital circuits. That was Vitesse's smallest process, after which they stopped making new GaAs CMOS. They've lost immense amounts of money since then and became essentially worthless. In April of this year Microsemi acquired the pathetic remains.

Comment Re:What goes around, comes around (Score 1) 90 90

GaAs has a better match to the visible spectrum than Si (not much IR response in GaAs due to the larger bandgap). This was valuable particularly for film cameras, as common films were not IR sensitive.

The response speed of silicon is plenty fast. Prior to the use of silicon, cadmium sulfide and cadmium selenide (IIRC) were used in light meters, and their method of operation was much different from silicon photodiodes. CdS was used as a bulk photoresistor, and due to inherent multiplication properties was much more sensitive than silicon. The disadvantages were that the multiplication process made the devices slow, and shoddy design and manufacturing techniques caused the devices to degrade and become useless after a couple of decades.

Comment Re:I never understand the point of that (Score 1) 471 471

A T-shirt is a short-sleeved collarless shirt with an unadjustable opening to put your head through, made of a thin, soft knitted material (usually cotton). If it's sleeveless or long-sleeved, it's not a T-shirt. If the shirt opens in back or in front, or if the neck opening buttons up, it's not a T-shirt. If it has a collar, it's not a T-shirt. If it's made of flannel, leather, shiny plastic or chain mail, it's not a T-shirt. If it's woven, not knitted, it's not a T-shirt. That leaves a lot of possibilities beyond T-shirt and bare-chested.

How can you do 'New Math' problems with an 'Old Math' mind? -- Charles Schulz

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