On Tue, 17 Jan 2006 13:23:41 +0100, Stef Mientki wrote:> bill.sloman@ieee.org wrote: >> Stef Mientki wrote: >>>John Larkin wrote: >>>>On Mon, 16 Jan 2006 16:30:03 -0500, Spehro Pefhany >>>>>On Mon, 16 Jan 2006 13:06:15 -0800, the renowned John Larkin >>>>>>On 14 Jan 2006 18:34:13 -0800, bill.sloman@ieee.org wrote: >>>>>> >>>>>>>>Why do you need 1 ps jitter? >>>>>>> >>>>>>>I'd put my money on the "idiot manager" option. Idiot systems engineers >>>>>>>also exist - "we've got this circuit which introduces 99psec of jitter, >>>>>>>and the error budget is 100psec, so the clock can't introduce more than >>>>>>>1psec of additional jitter". >>>>>> >>>>>>Probably the same guy that was upgrading to a 32-bit CPU and needed a >>>>>>32-bit ADC to match. >>>>> >>>>>bits ~= dB/6 >>>> >>>>So 32 bits is 192 dB. Isn't that just about the ratio of 1 atm to the >>>>threshold of hearing? >>> >>>Technici should be open minded: >>> "nothing is impossible untill it's proven" >>>at my work we've a 128 channel 32 (or 34) bit AD converter !! >> >> I didn't know that Radboud University was collaborating in the gravity >> wave detector experiments .... > > I think that's Leiden, > we're just looking for brain waves.It'd be interesting to do an experiment where you sense magnetic fields in the body during emotional stimulation - i.e., like watching a good movie, or listening to some good music, or picking a fight... Cheers! Rich
1pSec Jitter
Started by ●January 14, 2006
Reply by ●January 17, 20062006-01-17
Reply by ●January 17, 20062006-01-17
Keith wrote:> On Mon, 16 Jan 2006 23:15:40 +0000, Rich Grise wrote: > > >>On Mon, 16 Jan 2006 17:45:37 -0500, Spehro Pefhany wrote: >> >>>On Mon, 16 Jan 2006 13:55:42 -0800, the renowned John Larkin >>> >>>>On Mon, 16 Jan 2006 16:30:03 -0500, Spehro Pefhany >>>> >>>>>On Mon, 16 Jan 2006 13:06:15 -0800, the renowned John Larkin >>>>> >>>>>>On 14 Jan 2006 18:34:13 -0800, bill.sloman@ieee.org wrote: >>>>>> >>>>>>>>Why do you need 1 ps jitter? >>>>>>> >>>>>>>I'd put my money on the "idiot manager" option. Idiot systems engineers >>>>>>>also exist - "we've got this circuit which introduces 99psec of jitter, >>>>>>>and the error budget is 100psec, so the clock can't introduce more than >>>>>>>1psec of additional jitter". >>>>>> >>>>>>Probably the same guy that was upgrading to a 32-bit CPU and needed a >>>>>>32-bit ADC to match. >>>>> >>>>>bits ~= dB/6 >>>> >>>>So 32 bits is 192 dB. Isn't that just about the ratio of 1 atm to the >>>>threshold of hearing? >>> >>>This web page says < 1E9, so >180dB. >>> >>>http://hyperphysics.phy-astr.gsu.edu/hbase/sound/intens.html >>> >>>by their info the threshold of pain is 0.003 of 1 atm. >>> >>>I guess things would get nonlinear when you start to approach one bar >>>even if it didn't rupture your eardrums. >> >>Have you ever seen that stock footage of a nuke? There's a very visible >>shock wave of some kind, that's obviously traveling faster than Mach 1. > > > Supersonic shock waves. What's next?! >All shock waves are supersonic. That's why it's a shock wave and not an ordinary sound wave. There's a big increase in entropy in its wake, too. Cheers, Phil Hobbs
Reply by ●January 17, 20062006-01-17
On Tue, 17 Jan 2006 11:56:33 -0500, Phil Hobbs wrote:> Keith wrote: >> On Mon, 16 Jan 2006 23:15:40 +0000, Rich Grise wrote: >> >> >>>On Mon, 16 Jan 2006 17:45:37 -0500, Spehro Pefhany wrote: >>> >>>>On Mon, 16 Jan 2006 13:55:42 -0800, the renowned John Larkin >>>> >>>>>On Mon, 16 Jan 2006 16:30:03 -0500, Spehro Pefhany >>>>> >>>>>>On Mon, 16 Jan 2006 13:06:15 -0800, the renowned John Larkin >>>>>> >>>>>>>On 14 Jan 2006 18:34:13 -0800, bill.sloman@ieee.org wrote: >>>>>>> >>>>>>>>>Why do you need 1 ps jitter? >>>>>>>> >>>>>>>>I'd put my money on the "idiot manager" option. Idiot systems engineers >>>>>>>>also exist - "we've got this circuit which introduces 99psec of jitter, >>>>>>>>and the error budget is 100psec, so the clock can't introduce more than >>>>>>>>1psec of additional jitter". >>>>>>> >>>>>>>Probably the same guy that was upgrading to a 32-bit CPU and needed a >>>>>>>32-bit ADC to match. >>>>>> >>>>>>bits ~= dB/6 >>>>> >>>>>So 32 bits is 192 dB. Isn't that just about the ratio of 1 atm to the >>>>>threshold of hearing? >>>> >>>>This web page says < 1E9, so >180dB. >>>> >>>>http://hyperphysics.phy-astr.gsu.edu/hbase/sound/intens.html >>>> >>>>by their info the threshold of pain is 0.003 of 1 atm. >>>> >>>>I guess things would get nonlinear when you start to approach one bar >>>>even if it didn't rupture your eardrums. >>> >>>Have you ever seen that stock footage of a nuke? There's a very visible >>>shock wave of some kind, that's obviously traveling faster than Mach 1. >> >> >> Supersonic shock waves. What's next?! >> > > All shock waves are supersonic. That's why it's a shock wave and not an > ordinary sound wave. There's a big increase in entropy in its wake, too. > > Cheers, > > Phil HobbsYears ago, I saw a satellite video of Mt. St. Helens going off, and it sent out what must have been a shock wave all the way to the next-door states. In the vid, it happened in seconds, but I have no idea what the time-scale was compared to real-time. But it looked like the sort of condensation wave that you see with shock waves. I've done a little searching, but haven't really found out anything about it, and I guess MSH is pretty much old news these days. Thanks, Rich
Reply by ●January 17, 20062006-01-17
> Now if we could only find a microphone and preamp > to cover the entire range ...Then you'd have to buy the amp and speaker to reproduce the recording! Tim.
Reply by ●January 17, 20062006-01-17
Stef Mientki wrote:> bill.sloman@ieee.org wrote: > > Stef Mientki wrote: > > > >>Ico wrote: > >> > >>>In comp.arch.embedded Stef Mientki <S.Mientki-nospam@mailbox.kun.nl> wrote: > >>> > >>> > >>> > >>>>at my work we've a 128 channel 32 (or 34) bit AD converter !! > >>> > >>> > >>>Just curious: what is it used for ? > >>> > >> > >>magnetoencephalography (MEG), functional brain imaging, > >>by measuring the magnetic field form active neurons with squids. > > > > > > Working for Peter Hagoort? > > > No, at the ID"ID" ? The Donders Centre does have an MEG http://www.ru.nl/aspx/get.aspx?xdl=/views/run/xdl/page&SitIdt=119&VarIdt=96&ItmIdt=18668 but I guess you'd have to be tied up to the Radboud hospital http://www.ru.nl/aspx/get.aspx?xdl=/views/run/xdl/page&SitIdt=119&VarIdt=96&ItmIdt=18668 but none of the departments listed there seem to qualify as "ID" -- Bill Sloman, Nijmegen
Reply by ●January 18, 20062006-01-18
Phil Hobbs wrote:> Keith wrote:[snip]>> >> Supersonic shock waves. What's next?! >> > > All shock waves are supersonic. That's why it's a shock wave and not an > ordinary sound wave. There's a big increase in entropy in its wake, too. >Is a supersonic shockwave the explanation of the effect one sometimes notices with a nearby lightning strike: see the flash, & hear almost simultaneously a sharp crack, like a stick snapping. A second or so later, comes the boom. So that crack must have been supersonic?
Reply by ●January 18, 20062006-01-18
In article <43ce15a6$0$23587$5a62ac22@per-qv1-newsreader-01.iinet.net.au>, David R Brooks <davebXXX@iinet.net.au> wrote:>Phil Hobbs wrote: >> Keith wrote: >[snip] >>> >>> Supersonic shock waves. What's next?! >>> >> >> All shock waves are supersonic. That's why it's a shock wave and not an >> ordinary sound wave. There's a big increase in entropy in its wake, too. >> >Is a supersonic shockwave the explanation of the effect one sometimes >notices with a nearby lightning strike: see the flash, & hear almost >simultaneously a sharp crack, like a stick snapping. A second or so >later, comes the boom. So that crack must have been supersonic?Did the "sharp crack" come out of your radio? -- -- kensmith@rahul.net forging knowledge
Reply by ●January 18, 20062006-01-18
In article <pan.2006.01.17.16.56.00.384477@example.net>, Rich Grise <richgrise@example.net> wrote: [...]>It'd be interesting to do an experiment where you sense magnetic fields >in the body during emotional stimulation - i.e., like watching a good >movie, or listening to some good music, or picking a fight...If you are measuring the field in the body, you have to insert the magnetometer. I don't think we'd hear the music over the "OUCH". BTW: The heart pumping makes some magnetic noise you'd have to filter out before you could start looking for other stuff. -- -- kensmith@rahul.net forging knowledge
Reply by ●January 18, 20062006-01-18
David R Brooks wrote:> > [snip] >> > Is a supersonic shockwave the explanation of the effect one > sometimes notices with a nearby lightning strike: see the flash, > & hear almost simultaneously a sharp crack, like a stick > snapping. A second or so later, comes the boom. So that crack > must have been supersonic?Much simpler explanation. The speed of sound varies with frequency. -- "If you want to post a followup via groups.google.com, don't use the broken "Reply" link at the bottom of the article. Click on "show options" at the top of the article, then click on the "Reply" at the bottom of the article headers." - Keith Thompson More details at: <http://cfaj.freeshell.org/google/>
Reply by ●January 18, 20062006-01-18
On Wed, 18 Jan 2006 09:59:41 -0500, "Chuck F. " <cbfalconer@yahoo.com> wrote:>David R Brooks wrote: >> >> [snip] >>> >> Is a supersonic shockwave the explanation of the effect one >> sometimes notices with a nearby lightning strike: see the flash, >> & hear almost simultaneously a sharp crack, like a stick >> snapping. A second or so later, comes the boom. So that crack >> must have been supersonic? > >Much simpler explanation. The speed of sound varies with frequency.Or more likely that the audio attenuation is frequency (and temperature dependant). If you have a lightning that hits close to you, it might still be 1-2 km long. You will hear the local hit immediately with all high frequency components present. However, the sound from the tail of the lightning will arrive 6 seconds later with all high frequency components attenuated and you will just hear the rumble. Paul
