[time-nuts] Neutrinos not so fast? (defectove connector)
azelio.boriani at screen.it
Thu Feb 23 14:51:35 UTC 2012
And by using a differential pair is like halving the rise time: when one
arm rises the other falls, effectively doubling the speed of the crossing
and the sharpening of the trigger event. Sort of auto_ schmitt_trigger...
On Thu, Feb 23, 2012 at 3:45 PM, Azelio Boriani <azelio.boriani at screen.it>wrote:
> I recommend the differential pair: here the trigger have to sense the
> crossing of the two signals and this crossing is well definite.
> On Thu, Feb 23, 2012 at 3:36 PM, Jim Lux <jimlux at earthlink.net> wrote:
>> On 2/23/12 6:24 AM, Alberto di Bene wrote:
>>> On 2/23/2012 1:04 AM, Poul-Henning Kamp wrote:
>>> I simply don't buy the story that tightening the connector makes
>>> a consistent 60 nanoseconds difference on a signal.
>>> I spoke with a physicist of Cern, friend of the leader of the team
>>> performed the Opera experiment.
>>> He told me that the badly seated connector caused the amplitude of the
>>> signal to be lower, and for this reason the trigger point, which was
>>> set at a specific level, was reached 60ns later.
>>> 73 Alberto I2PHD
>> Darn those finite rise times<grin>
>> I've been bitten more than once by this very phenomenon (which I admit
>> doesn't say a lot for me.. being bitten once is ok, but since I've had
>> multiple bites...)
>> But this brings up an interesting time-nut problem for the hive mind..
>> If you had to design some scheme for interconnecting "boxes" and wanted
>> to transmit an accurate time sync, what should it look like, so that you're
>> insensitive to things like rise time.
>> (maybe this harkens back to the discussion about 10 MHz, why sine vs
>> square wave distribution)
>> It has to be a single signal (maybe a differential pair), because
>> otherwise, don't you have potential for skew between the multiple signals.
>> Zerocrossing sort of works, if you take only one direction, but does
>> asymmetry of the waveform screw you up? (e.g. what's "zero".. is it half
>> way between peak values + and -?)
>> time-nuts mailing list -- time-nuts at febo.com
>> To unsubscribe, go to
>> and follow the instructions there.
More information about the time-nuts