Re: [time-nuts] 60 Hz frequency and phase measurement
On 7/2/19 4:09 PM, Dana Whitlow wrote: I've always noted that casual attempts to pick up 60 Hz with small antennas etc see more harmonics and other trash than actual line frequency. But if you're in an office environment, why not plug something in? It's quite easy to build a simple passive diode clipper/filter that will plug into a wall outlet and which will provide a sort of soft (but clean) squarewave at a voltage level convenient for lab instruments and with good protection against big spikes and other trash riding on the line. Safety approvals are one obstacle (of course one could use a AC wall wart). Actually, it's because someone asked me about a science experiment where you'd place them in a neighborhood outdoors. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] 60 Hz frequency and phase measurement
I built a 6 Volt filament transformer into a small metal box and connected the secondary to a couple of 5-way banana jacks. In addition to the 6 Volt output, I put a 100KΩ pot across the terminals with the wiper connected to a third jack. That way, I can have any voltage from 0 to 6 VAC, avoiding possible damage to sensitive front ends. Jeremy On Tue, Jul 2, 2019 at 8:00 PM Gerhard Hoffmann wrote: > > Am 03.07.19 um 01:25 schrieb Tim Shoppa: > > Jim, most of us are satisfied to use a 6.3VAC filament transformer to > step down from 120VAC and isolate from the power line. > > Exactly. I used an old 6 or 9V AC wall wart and a resistive 1:3 divider > last year when the European grid frequency was low because of some > trouble in the distant south-east. That gave a really stable reading. > > < > > https://www.flickr.com/photos/137684711@N07/38870750440/in/dateposted-public/ >> > > > regards, Gerhard > > > > > > ___ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. > -- Jeremy Nichols Sent from my iPad 6. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] 60 Hz frequency and phase measurement
Am 03.07.19 um 01:25 schrieb Tim Shoppa: Jim, most of us are satisfied to use a 6.3VAC filament transformer to step down from 120VAC and isolate from the power line. Exactly. I used an old 6 or 9V AC wall wart and a resistive 1:3 divider last year when the European grid frequency was low because of some trouble in the distant south-east. That gave a really stable reading. < https://www.flickr.com/photos/137684711@N07/38870750440/in/dateposted-public/ > regards, Gerhard ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] TimeLab phase difference (slope sec/sec)
Hi Bob, I'm seeing 4.22E-12 as the slope value in the upper right of the TimeLab phase difference plot. Is that telling me that my DUT is within +4.22ps / sec from my reference 1PPS for the 24 hour measurement duration? I have attached a screen capture that will hopefully make its way through for viewing. Thanks, Chris On 07/02/19 11:50:10, Bob kb8tq wrote: Hi The difference in seconds between the start phase and the end phase divided by the number of seconds duration gives you the parts in whatever of the error. If you see 1us ( = 1x10^-6 seconds) of change in a second, you are off by 1 ppm (or 1x10^-6). If you see 1 us of change in 1,000 seconds you are off by 1 ppb (or 1x10^-9). At a bit over 10 days (1,000,000 seconds) your 1 us change is 1 ppt (or 1x10^-12). Bob On Jul 2, 2019, at 10:17 AM, Chris Burford wrote: Is the slope value for the phase difference shown in TimeLab an average of the overall data sample duration? The reason I ask is that my service manual for my RFS says: /"//A faster way to make the comparison between the reference frequency and the DUT is to use the time interval measurement mode of the counters. In this case, the time intervals between the 10MHz zero crossings of the reference frequency and the DUT are measured and averaged. If this time interval changes by less than 10ps per second, then the DUT is within 1 part in //10^11 of the frequency reference."/ I'm just curious if the phase difference slope value can be plugged in to this equation. Regards, Chris ___ time-nuts mailing list --time-nuts@lists.febo.com To unsubscribe, go tohttp://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there. ___ time-nuts mailing list --time-nuts@lists.febo.com To unsubscribe, go tohttp://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] 60 Hz frequency and phase measurement
Jim, most of us are satisfied to use a 6.3VAC filament transformer to step down from 120VAC and isolate from the power line. Tim N3QE > On Jul 2, 2019, at 5:56 PM, jimlux wrote: > > There's some designs on the list (using a PICPET, for instance) to measure > the local line frequency and phase.. > > but the schemes we've discussed require connecting to the power line in some > way. > > What about a non-contact sensing approach? Something you could put in a box > and it would pick up the electric or magnetic field as the input? > > Just how strong is the field anyway? I've always been trying to cancel or > shield it or reduce it in some way, so I've never actually measured it in a > calibrated way. A 10cm antenna on a 1Meg scope probe looks like about 40 mV > peak to peak (for the 60 Hz component) along with lots of other high > frequency stuff (40 kHz and a few hundred kHz in my office) from switching > power supplies. > > I realize that in a office/industrial area you'll probably pick up all three > phases in some way. > > What about using a small loop? or a magnetoresistive sensor (like the > compasses in phones)? > > Has anyone tried any of these? > > > > ___ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] TimeLab phase difference (slope sec/sec)
Hi The gotcha is that if the duration gets long enough, the numbers on a GPSDO will get silly small. You very much have to decide what time duration is appropriate to your system / application. If you always run your frequency counter on a 1 or 10 second gate …. you really don’t care about 10,000 seconds. Bob > On Jul 2, 2019, at 7:15 PM, Chris Burford wrote: > > Hi Bob, > > I'm seeing 4.22E-12 as the slope value in the upper right of the TimeLab > phase difference plot. Is that telling me that my DUT is within +4.22ps / sec > from my reference 1PPS for the 24 hour measurement duration? > > I have attached a screen capture that will hopefully make its way through for > viewing. > > Thanks, > > Chris > > On 07/02/19 11:50:10, Bob kb8tq wrote: >> Hi >> >> The difference in seconds between the start phase and the end phase divided >> by the number >> of seconds duration gives you the parts in whatever of the error. >> >> If you see 1us ( = 1x10^-6 seconds) of change in a second, you are off by 1 >> ppm (or 1x10^-6). >> If you see 1 us of change in 1,000 seconds you are off by 1 ppb (or >> 1x10^-9). At a bit over 10 >> days (1,000,000 seconds) your 1 us change is 1 ppt (or 1x10^-12). >> >> Bob >> >>> On Jul 2, 2019, at 10:17 AM, Chris Burford wrote: >>> >>> Is the slope value for the phase difference shown in TimeLab an average of >>> the overall data sample duration? The reason I ask is that my service >>> manual for my RFS says: >>> >>> /"//A faster way to make the comparison between the reference frequency and >>> the DUT is to use the time interval measurement mode of the counters. In >>> this case, the time intervals between the 10MHz zero crossings of the >>> reference frequency and the DUT are measured and averaged. If this time >>> interval changes by less than 10ps per second, then the DUT is within 1 >>> part in //10^11 of the frequency reference."/ >>> >>> I'm just curious if the phase difference slope value can be plugged in to >>> this equation. >>> >>> Regards, >>> >>> Chris >>> >>> >>> ___ >>> time-nuts mailing list --time-nuts@lists.febo.com >>> To unsubscribe, go >>> tohttp://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com >>> and follow the instructions there. >> ___ >> time-nuts mailing list --time-nuts@lists.febo.com >> To unsubscribe, go >> tohttp://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com >> and follow the instructions there. > ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] 60 Hz frequency and phase measurement
I've always noted that casual attempts to pick up 60 Hz with small antennas etc see more harmonics and other trash than actual line frequency. But if you're in an office environment, why not plug something in? It's quite easy to build a simple passive diode clipper/filter that will plug into a wall outlet and which will provide a sort of soft (but clean) squarewave at a voltage level convenient for lab instruments and with good protection against big spikes and other trash riding on the line. If you're willing to do this and need help with a design, contact me off-list at k8yumdoo...@gmail.com. Dana On Tue, Jul 2, 2019 at 6:00 PM jimlux wrote: > There's some designs on the list (using a PICPET, for instance) to > measure the local line frequency and phase.. > > but the schemes we've discussed require connecting to the power line in > some way. > > What about a non-contact sensing approach? Something you could put in a > box and it would pick up the electric or magnetic field as the input? > > Just how strong is the field anyway? I've always been trying to cancel > or shield it or reduce it in some way, so I've never actually measured > it in a calibrated way. A 10cm antenna on a 1Meg scope probe looks like > about 40 mV peak to peak (for the 60 Hz component) along with lots of > other high frequency stuff (40 kHz and a few hundred kHz in my office) > from switching power supplies. > > I realize that in a office/industrial area you'll probably pick up all > three phases in some way. > > What about using a small loop? or a magnetoresistive sensor (like the > compasses in phones)? > > Has anyone tried any of these? > > > > ___ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. > ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] 60 Hz frequency and phase measurement
There's some designs on the list (using a PICPET, for instance) to measure the local line frequency and phase.. but the schemes we've discussed require connecting to the power line in some way. What about a non-contact sensing approach? Something you could put in a box and it would pick up the electric or magnetic field as the input? Just how strong is the field anyway? I've always been trying to cancel or shield it or reduce it in some way, so I've never actually measured it in a calibrated way. A 10cm antenna on a 1Meg scope probe looks like about 40 mV peak to peak (for the 60 Hz component) along with lots of other high frequency stuff (40 kHz and a few hundred kHz in my office) from switching power supplies. I realize that in a office/industrial area you'll probably pick up all three phases in some way. What about using a small loop? or a magnetoresistive sensor (like the compasses in phones)? Has anyone tried any of these? ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] TimeLab phase difference (slope sec/sec)
Hi The difference in seconds between the start phase and the end phase divided by the number of seconds duration gives you the parts in whatever of the error. If you see 1us ( = 1x10^-6 seconds) of change in a second, you are off by 1 ppm (or 1x10^-6). If you see 1 us of change in 1,000 seconds you are off by 1 ppb (or 1x10^-9). At a bit over 10 days (1,000,000 seconds) your 1 us change is 1 ppt (or 1x10^-12). Bob > On Jul 2, 2019, at 10:17 AM, Chris Burford wrote: > > Is the slope value for the phase difference shown in TimeLab an average of > the overall data sample duration? The reason I ask is that my service manual > for my RFS says: > > /"//A faster way to make the comparison between the reference frequency and > the DUT is to use the time interval measurement mode of the counters. In this > case, the time intervals between the 10MHz zero crossings of the reference > frequency and the DUT are measured and averaged. If this time interval > changes by less than 10ps per second, then the DUT is within 1 part in > //10^11 of the frequency reference."/ > > I'm just curious if the phase difference slope value can be plugged in to > this equation. > > Regards, > > Chris > > > ___ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] TimeLab phase difference (slope sec/sec)
Is the slope value for the phase difference shown in TimeLab an average of the overall data sample duration? The reason I ask is that my service manual for my RFS says: /"//A faster way to make the comparison between the reference frequency and the DUT is to use the time interval measurement mode of the counters. In this case, the time intervals between the 10MHz zero crossings of the reference frequency and the DUT are measured and averaged. If this time interval changes by less than 10ps per second, then the DUT is within 1 part in //10^11 of the frequency reference."/ I'm just curious if the phase difference slope value can be plugged in to this equation. Regards, Chris ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
