Re: [ntp:questions] Loop Filter Gains vs. Polling Interval

2011-05-16 Thread Harlan Stenn
Oh, you may also discover that 'burst' is *not* your friend. H ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions

Re: [ntp:questions] Loop Filter Gains vs. Polling Interval

2011-05-16 Thread David L. Mills
Edward, The loop time constant varies directly with the poll interval. See "How NTP Works" in the current documentation. Note that the default value and range are purposely optimized for public time servers in order to manage network overhead and are not appropriate for the most accurate LAN

Re: [ntp:questions] Loop Filter Gains vs. Polling Interval

2011-05-16 Thread Richard B. Gilbert
On 5/14/2011 1:23 PM, Mischanko, Edward T wrote: Can anyone tell me, does the sensitivity for frequency adjustment lessen as the polling interval increases? I ask because I'm observing that my offset increases and the frequency adjustment decreases to the point I fall out of sync at polling inte

Re: [ntp:questions] Stratum 1 GPS Network Time Servers

2011-05-16 Thread Richard B. Gilbert
On 5/12/2011 3:14 AM, Alan Decelis wrote: In the context of a requirement to set up a redundant configuration of internal (peered) GPS Network Time Servers that operate at Stratum 1, is there a best practice of the number of GPS Network Time Servers to set? Would it be risky to rely on two reliab

Re: [ntp:questions] Stratum 1 GPS Network Time Servers

2011-05-16 Thread E-Mail Sent to this address will be added to the BlackLists
Chris Albertson wrote: > You don't need an expensive computer. > An older computer works fine ... > Just make sure it has a real RS232 serial port > and not a USB/Serial converter. Many pieces of existing network equipment can also double task as a LAN NTP Server, enterprise routers, web servers

Re: [ntp:questions] Loop Filter Gains vs. Polling Interval

2011-05-16 Thread David Woolley
Mischanko, Edward T wrote: How do I adjust the loop time constant so that it is shorter?? Looking at some recentish code, it looks like the time constant and poll interval are in a constant relation and the oversampling rate can't change. This for PLL mode. However, I think you should rea

Re: [ntp:questions] Another happy "Sure" GPS user

2011-05-16 Thread David Lord
Nickolay Orekhov wrote: PPS will be marked as falseticker when no "prefer" peer available. Do you set "prefer" for your GPS ? 2011/5/14 David Lord xPPS(2) .PPSb. 0 l3 16 3770.000 -0.003 0.004 I had "noselect" so that my network time was safe in case there was an

Re: [ntp:questions] Loop Filter Gains vs. Polling Interval

2011-05-16 Thread Harlan Stenn
Edward wrote: > How do I adjust the loop time constant so that it is shorter?? First, I will offer my favorite "between the lines" Bible quote: Blessed are those who get what they deserve which is similar to "Be careful what you wish for". You should be able to ... make whatever adjustments y

Re: [ntp:questions] Loop Filter Gains vs. Polling Interval

2011-05-16 Thread Mischanko, Edward T
Dave, How do I adjust the loop time constant so that it is shorter?? >> The integral component should be retained. The effect of having too >> long a loop time constant should be that the system fails to track clock >> wander, so would be more vulnerable to temperature changes or forgetting

Re: [ntp:questions] Loop Filter Gains vs. Polling Interval

2011-05-16 Thread David Woolley
David Woolley wrote: ecause I'm observing that my They are linked, but I have a feeling that the loop time constant is not For clarity, it is the frequency response that varies, but that does mean that the gain for fast variations reduces. Note that, because of the oversampling, the cut of

Re: [ntp:questions] Loop Filter Gains vs. Polling Interval

2011-05-16 Thread David Woolley
Mischanko, Edward T wrote: Can anyone tell me, does the sensitivity for frequency adjustment lessen as the polling interval increases? I ask because I'm observing that my They are linked, but I have a feeling that the loop time constant is not clamped, even though the poll interval is. The a