On Mon, 16 Jan 2006 13:06:15 -0800, the renowned John Larkin <jjlarkin@highNOTlandTHIStechnologyPART.com> wrote:>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. > >Johnbits ~= dB/6 Best regards, Spehro Pefhany -- "it's the network..." "The Journey is the reward" speff@interlog.com Info for manufacturers: http://www.trexon.com Embedded software/hardware/analog Info for designers: http://www.speff.com
1pSec Jitter
Started by ●January 14, 2006
Reply by ●January 16, 20062006-01-16
Reply by ●January 16, 20062006-01-16
On Mon, 16 Jan 2006 16:30:03 -0500, Spehro Pefhany <speffSNIP@interlogDOTyou.knowwhat> wrote:>On Mon, 16 Jan 2006 13:06:15 -0800, the renowned John Larkin ><jjlarkin@highNOTlandTHIStechnologyPART.com> wrote: > >>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. >> >>John > >bits ~= dB/6 > >So 32 bits is 192 dB. Isn't that just about the ratio of 1 atm to the threshold of hearing? John
Reply by ●January 16, 20062006-01-16
On Mon, 16 Jan 2006 13:55:42 -0800, the renowned John Larkin <jjlarkin@highNOTlandTHIStechnologyPART.com> wrote:>On Mon, 16 Jan 2006 16:30:03 -0500, Spehro Pefhany ><speffSNIP@interlogDOTyou.knowwhat> wrote: > >>On Mon, 16 Jan 2006 13:06:15 -0800, the renowned John Larkin >><jjlarkin@highNOTlandTHIStechnologyPART.com> wrote: >> >>>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. >>> >>>John >> >>bits ~= dB/6 >> >> > >So 32 bits is 192 dB. Isn't that just about the ratio of 1 atm to the >threshold of hearing? > >John >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. Best regards, Spehro Pefhany -- "it's the network..." "The Journey is the reward" speff@interlog.com Info for manufacturers: http://www.trexon.com Embedded software/hardware/analog Info for designers: http://www.speff.com
Reply by ●January 16, 20062006-01-16
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. Cheers! Rich
Reply by ●January 16, 20062006-01-16
On Mon, 16 Jan 2006 13:55:42 -0800, John Larkin wrote:>On Mon, 16 Jan 2006 16:30:03 -0500, Spehro Pefhany wrote: >>On Mon, 16 Jan 2006 13:06:15 -0800, the renowned John Larkin wrote: >>>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?Yep, 20 uPa RMS to 1 ATM or 101 kPa RMS is 0 to 194 dB SPL; from the lowest threshold of hearing for sensitive youngsters to sound levels on the launchpad during a large rocket launch, way into the nonlinear region. Now if we could only find a microphone and preamp to cover the entire range ...
Reply by ●January 16, 20062006-01-16
Rich Grise <richgrise@example.net> wrote:>On Mon, 16 Jan 2006 17:45:37 -0500, Spehro Pefhany wrote: >..... >> >> 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. > >Cheers! >Rich***Warning***Off-topic***Warning If you are talking about the "stock footage of a nuke" that I think you are talking about, I believe that spherical front is a visualization of the Cherenkov Effect. See: http://almaz.com/nobel/physics/cherenkov.html http://www.gae.ucm.es/~emma/tesina/node4.html Roberto Waltman [ Please reply to the group, ] [ return address is invalid. ]
Reply by ●January 16, 20062006-01-16
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?! -- Keith
Reply by ●January 16, 20062006-01-16
On Mon, 16 Jan 2006 17:45:37 -0500, Spehro Pefhany <speffSNIP@interlogDOTyou.knowwhat> wrote:>On Mon, 16 Jan 2006 13:55:42 -0800, the renowned John Larkin ><jjlarkin@highNOTlandTHIStechnologyPART.com> wrote: > >>On Mon, 16 Jan 2006 16:30:03 -0500, Spehro Pefhany >><speffSNIP@interlogDOTyou.knowwhat> wrote: >> >>>On Mon, 16 Jan 2006 13:06:15 -0800, the renowned John Larkin >>><jjlarkin@highNOTlandTHIStechnologyPART.com> wrote: >>> >>>>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. >>>> >>>>John >>> >>>bits ~= dB/6 >>> >>> >> >>So 32 bits is 192 dB. Isn't that just about the ratio of 1 atm to the >>threshold of hearing? >> >>John >> > >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. > >Clips the negative swings, for sure. John
Reply by ●January 17, 20062006-01-17
John Larkin wrote:> On Mon, 16 Jan 2006 16:30:03 -0500, Spehro Pefhany > <speffSNIP@interlogDOTyou.knowwhat> wrote: > > >>On Mon, 16 Jan 2006 13:06:15 -0800, the renowned John Larkin >><jjlarkin@highNOTlandTHIStechnologyPART.com> wrote: >> >> >>>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. >>> >>>John >> >>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 !! Stef> > John > >
Reply by ●January 17, 20062006-01-17
Stef Mientki <S.Mientki-nospam@mailbox.kun.nl> writes:> John Larkin wrote: >>>> >>>>Probably the same guy that was upgrading to a 32-bit CPU and needed a >>>>32-bit ADC to match. >>>> >>>>John >>> >>> 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 !! > StefI was getting ~27 bits out of a ADS1252 (after averaging). That is only a $6 part. -- John Devereux
