[ntp:questions] Re: drifting on crystal
brad at stop.mail-abuse.org
Thu Jan 13 08:42:49 UTC 2005
At 6:33 AM +0000 2005-01-13, Marc Brett wrote:
> That's the hardware cost. How many watts does it consume?
No more than the low-quality oscillator that is actually included
by the hardware vendor.
> why would an engineer include a component with "oven" in its
> name if he didn't have to?
There is no actual oven included with the crystal. The issue is
that the OXCO has gone through a more rigorous testing process which
includes testing in an oven, and has been certified to work to
certain tighter performance standards than your average everyday
crystal, and either actively compensates for temperature variations
or is relatively immune to them.
When CPUs are made, at first no one knows how fast a given chip
will run. It has to be tested first. Ones that are stable up to a
slower speed are sold at a lower price, while ones that are stable to
higher speeds will be sold for higher prices -- even if they were
made from the same block of silicon, and in fact were sitting right
next to each other when the masks were being laid down.
Same deal for crystal oscillators. Those that pass the more
stringent tests are sold for more money, those that don't are sold
for less. But other than the passing of the tests (or failure to
pass), there are no human-discernible differences between the two
components. One will get painted a different color than the other,
so that the manufacturer can tell the difference between them, and
know which one to sell for which price.
> Also, how many people really need that level of
Many people could benefit from it. Indeed, most everyone who
uses a computer could benefit from having a better clock, even if
they don't know it.
> If hundreds of millions of PCs are consuming watts they don't need,
> that's wasteful on a pretty grand scale.
There's no waste of power here. There is short-sightedness on
the part of the PC manufacturers, and a willingness to cut off their
nose to spite their face. That's all.
Brad Knowles, <brad at stop.mail-abuse.org>
"Those who would give up essential Liberty, to purchase a little
temporary Safety, deserve neither Liberty nor Safety."
-- Benjamin Franklin (1706-1790), reply of the Pennsylvania
Assembly to the Governor, November 11, 1755
SAGE member since 1995. See <http://www.sage.org/> for more info.
More information about the questions