Re: [time-nuts] Does a frequency counter locked to GPS need to "warm up"?
Exactly what I have run into. Some systems lock an internal reference to to the incoming system. So that oven has to come up to temp. Then the trigger and interpolators need to warm up and stabilize. So the really right answer is what accuracy are you looking for? Because what I mention above may simply not matter. Regards Paul WB8TSL On Thu, Feb 8, 2018 at 9:16 AM, Scott McGrathwrote: > Yes, You have removed the reference from the warmup but the input > circuits still need time to reach thermal equilibrium for most accurate > results > > > > On Feb 8, 2018, at 3:34 AM, Azelio Boriani > wrote: > > No warmup needed if the counter switches to the external reference. If > the counter uses the external reference to lock the internal one then > it is better to wait until the internal one is stable, maybe the > counter has a standby mode where it appears powered off but the > internal reference is active (usually an ovenized reference). For the > best performance (stability of trigger levels, input amplifiers and so > on) it is better to warmup the whole counter always. > > > On Thu, Feb 8, 2018 at 8:33 AM, Chris Wilson > wrote: > > > > > > 08/02/2018 07:31 > > > > Does a frequency counter connected to a permanently running > (Trimble Thunderbolt) GPS > > disciplined frequency standard need to warm up after switch on before > readings settle? > > Just curious, thanks. > > > > -- > > Best Regards, > > Chris Wilson. > > mailto: ch...@chriswilson.tv > > > > ___ > > time-nuts mailing list -- time-nuts@febo.com > > To unsubscribe, go to https://www.febo.com/cgi-bin/ > mailman/listinfo/time-nuts > > and follow the instructions there. > ___ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/ > mailman/listinfo/time-nuts > and follow the instructions there. > ___ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/ > mailman/listinfo/time-nuts > and follow the instructions there. > ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Does a frequency counter locked to GPS need to "warm up"?
Hi, Well, actually there is two methods: 1) Switch reference clock - a switch or mux changes which clock is being used. 2) Lock internal reference to external reference - a PLL lock of the internal reference to the external reference is enabled. For both, the counter core may need to heat up. For the first, the internal reference heatup can be ignored completely. For the second, the internal reference heatup cannot completely be ignored, it takes time for it to be within lock range and the lock-in behavior stabilizes. Still relatively quick, but an actual effect. At the end of the day, it depends on how precise you attempt to measure. Cheers, Magnus On 02/08/2018 03:16 PM, Scott McGrath wrote: > Yes, You have removed the reference from the warmup but the input circuits > still need time to reach thermal equilibrium for most accurate results > > > > On Feb 8, 2018, at 3:34 AM, Azelio Borianiwrote: > > No warmup needed if the counter switches to the external reference. If > the counter uses the external reference to lock the internal one then > it is better to wait until the internal one is stable, maybe the > counter has a standby mode where it appears powered off but the > internal reference is active (usually an ovenized reference). For the > best performance (stability of trigger levels, input amplifiers and so > on) it is better to warmup the whole counter always. > >> On Thu, Feb 8, 2018 at 8:33 AM, Chris Wilson wrote: >> >> >> 08/02/2018 07:31 >> >> Does a frequency counter connected to a permanently running (Trimble >> Thunderbolt) GPS >> disciplined frequency standard need to warm up after switch on before >> readings settle? >> Just curious, thanks. >> >> -- >> Best Regards, >> Chris Wilson. >> mailto: ch...@chriswilson.tv >> >> ___ >> time-nuts mailing list -- time-nuts@febo.com >> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. > ___ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > ___ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Does a frequency counter locked to GPS need to "warm up"?
Yes, You have removed the reference from the warmup but the input circuits still need time to reach thermal equilibrium for most accurate results On Feb 8, 2018, at 3:34 AM, Azelio Borianiwrote: No warmup needed if the counter switches to the external reference. If the counter uses the external reference to lock the internal one then it is better to wait until the internal one is stable, maybe the counter has a standby mode where it appears powered off but the internal reference is active (usually an ovenized reference). For the best performance (stability of trigger levels, input amplifiers and so on) it is better to warmup the whole counter always. > On Thu, Feb 8, 2018 at 8:33 AM, Chris Wilson wrote: > > > 08/02/2018 07:31 > > Does a frequency counter connected to a permanently running (Trimble > Thunderbolt) GPS > disciplined frequency standard need to warm up after switch on before > readings settle? > Just curious, thanks. > > -- > Best Regards, > Chris Wilson. > mailto: ch...@chriswilson.tv > > ___ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Does a frequency counter locked to GPS need to "warm up"?
Hi It depends a *lot* on the frequency counter. An old style “just count the number of edges” device should be good to go pretty fast. One of the “fry an egg on it” interpolating counters that get into the 20 ps range may well need some time to stabilize. If you are doing ADEV runs, a couple hours of warmup would be a good idea. Bob > On Feb 8, 2018, at 2:33 AM, Chris Wilsonwrote: > > > > 08/02/2018 07:31 > > Does a frequency counter connected to a permanently running (Trimble > Thunderbolt) GPS > disciplined frequency standard need to warm up after switch on before > readings settle? > Just curious, thanks. > > -- > Best Regards, > Chris Wilson. > mailto: ch...@chriswilson.tv > > ___ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Does a frequency counter locked to GPS need to "warm up"?
Hi, On 02/08/2018 08:33 AM, Chris Wilson wrote: > > > 08/02/2018 07:31 > > Does a frequency counter connected to a permanently running (Trimble > Thunderbolt) GPS > disciplined frequency standard need to warm up after switch on before > readings settle? > Just curious, thanks. > Well, while the internal reference is not directly steering, if it is being locked to the external reference, at least some warming up is needed before it is very stable. Also, depending on the details of the counters, high resolution interpolators may need warmup to perform well and for the autocal to perform meaningfull values. However, usually it's not very long times and often shaddowed by the internal referece anyway. Just to get a rough reading, no. If you want to trust it and trust the noise, let it warm up for half an hour or so. Cheers, Magnus ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Does a frequency counter locked to GPS need to "warm up"?
No warmup needed if the counter switches to the external reference. If the counter uses the external reference to lock the internal one then it is better to wait until the internal one is stable, maybe the counter has a standby mode where it appears powered off but the internal reference is active (usually an ovenized reference). For the best performance (stability of trigger levels, input amplifiers and so on) it is better to warmup the whole counter always. On Thu, Feb 8, 2018 at 8:33 AM, Chris Wilsonwrote: > > > 08/02/2018 07:31 > > Does a frequency counter connected to a permanently running (Trimble > Thunderbolt) GPS > disciplined frequency standard need to warm up after switch on before > readings settle? > Just curious, thanks. > > -- >Best Regards, >Chris Wilson. > mailto: ch...@chriswilson.tv > > ___ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] Does a frequency counter locked to GPS need to "warm up"?
08/02/2018 07:31 Does a frequency counter connected to a permanently running (Trimble Thunderbolt) GPS disciplined frequency standard need to warm up after switch on before readings settle? Just curious, thanks. -- Best Regards, Chris Wilson. mailto: ch...@chriswilson.tv ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.