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| Authored by: OpenSourceFTW on Thursday, November 29 2012 @ 06:07 PM EST |
A signal has no meaning in and of it self until someone assigns it.
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I voted for Groklaw (Legal Technology Category) in the 2012 ABA Journal Blawg
100. Did you? http://www.abajournal.com/blawg100. Voting ends Dec 21.[ Reply to This | Parent | # ]
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| Authored by: tknarr on Thursday, November 29 2012 @ 07:53 PM EST |
And in a lot of logic circuits no voltage is an undefined state. Common
levels for TTL logic, for instance, are +5 and -5 volts. 0 volts is in the
transition region and doesn't represent a valid binary value. It's also common
for levels to be ranges, eg. 0 is -2 volts or less and 1 is +2 volts or more,
allowing a certain tolerance for voltage variations.
More fun is that
usually the bits are latched so the transition voltage depends on the direction
of the transition. If the latch is 0, it flips to 1 only when the input signal
hits +2 volts rising. If it's 1, it flips to 0 only when the input signal hits
-2 volts falling. The input going from +5 volts to 0 volts and back up doesn't
trigger a transition. That provides tolerance against noise in the signals, not
just variations in voltage. [ Reply to This | Parent | # ]
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- Reverse Logic - Authored by: Anonymous on Friday, November 30 2012 @ 10:35 AM EST
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| Authored by: Ian Al on Sunday, December 02 2012 @ 06:17 AM EST |
One of the 19th century scientists decided that electricity flowed from a
positive charge to a negative charge. So, which terminal was positive and which,
negative? The answer they plumped for is still in use for cells and batteries to
this day.
Years later and they established that electicity was the flow of electrons.
Unfortunately, that's from negative to positive. The only answer was not that
the scientists had guessed wrong, but that the electrons had a negative electric
charge and were attracted uphill by the charge on the 'positive' terminal.
At a recent conference, protons and electrons could not agree on which was
positive. They agreed to let the current convention (sic) continue to stop folk
putting in batteries, upside down.
So, positive and negative? Just signs that have no intrinsic meaning to the
Universe, just to our puny human minds.
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Regards
Ian Al
Software Patents: It's the disclosed functions in the patent, stupid![ Reply to This | Parent | # ]
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