Re: [time-nuts] Precision DACs

is 122 dB signal to every thing else. On Mon, Jul 25, 2016 at 7:40 PM, Attila Kinali <att...@kinali.ch> wrote: > On Sun, 24 Jul 2016 23:48:05 -0400 > Scott Stobbe <scott.j.sto...@gmail.com> wrote: > > > I doubt the AD5791 does much better than 16 bits operating at 1 M

Re: [time-nuts] Precision DACs (was: NCOCXO anyone?)

I doubt the AD5791 does much better than 16 bits operating at 1 Msps, when you include glitch energy, noise, and distortion. On Saturday, 23 July 2016, Attila Kinali wrote: > On Fri, 22 Jul 2016 12:15:25 -0500 > David > wrote: > > > If you

Re: [time-nuts] LSEM (Leap Second Every Month)

cesium), and > changing any steps to be full +1 or -1 second integers (and not fractions) > was why UTC was created. > > /tvb > > - Original Message - > From: "Scott Stobbe" <scott.j.sto...@gmail.com> > To: "Discussion of precise time and frequency

Re: [time-nuts] NCOCXO anyone?

Capacitor matching (Moore's law) has improved for switch-cap designs. Also depends on the tuning gain, 10 ppm/V would be very demanding versus 10 ppb/V. On Thu, Jul 21, 2016 at 9:47 PM, Richard (Rick) Karlquist < rich...@karlquist.com> wrote: > > > On 7/21/2016 4:56 PM, Nick Sayer via time-nuts

Re: [time-nuts] Precision DACs

7/25/2016 10:42 PM, Scott Stobbe wrote: > >> >> dramatically different due to glitching on code transition. That being >> said, they are kept separate not to confuse sources of error. >> >> > FWIW: > > The 5071A has a "home brew" DDS that was de

Re: [time-nuts] LSEM (Leap Second Every Month)

If UTC time was adjusted every month would stick with one full second? Or some smaller quantity? On Thursday, 21 July 2016, Brooke Clarke wrote: > Hi Tom: > > I like this idea. I addresses the lesson from Y2K that something done > often works much better than something done

Re: [time-nuts] Very Accurate Delta Time RF Pulse Measurements

Taking a look for it also turned up a recent time-nuts thread https://www.febo.com/pipermail/time-nuts/2016-May/097801.html On Thursday, 28 July 2016, Scott Stobbe <scott.j.sto...@gmail.com> wrote: > There was a pic app note on alternate uses for the cap sense block a while > ba

Re: [time-nuts] Very Accurate Delta Time RF Pulse Measurements

There was a pic app note on alternate uses for the cap sense block a while back, not sure it that it will push you into the ps. On Thursday, 28 July 2016, Jerome Blaha wrote: > Hi Guys, > > This is a little outside of time-nuts scope, but not by much. I'm >

Re: [time-nuts] Q/noise of Earth as an oscillator

ged to a current Io, and then had its terminals crowbarred. Our solar time is like watching a reference electron run round and round a coil. Björn and Dave, thanks for the gyro reference I will take a look. On Fri, Jul 29, 2016 at 1:19 PM, Tom Van Baak <t...@leapsecond.com> wrote: > Scott

Re: [time-nuts] Q/noise of Earth as an oscillator

An irreversible process would be a better description versus energy loss. Like joule heating (resistance, friction). On Sunday, 31 July 2016, Hal Murray wrote: > > t...@radio.sent.com said: > > So loss effects frequency in one situation and amplitude in

Re: [time-nuts] controlling instruments using USB

In Windows, likely Mac/Linux with the NI visa library you get the IO trace to help debug applications. On Linux strace may give you some clues. On Monday, 25 July 2016, jimlux wrote: > Semi-off-topic.. > > I've got a bunch of Keysight/Agilent/HP instruments with USB

Re: [time-nuts] Effect of EFC noise on phase noise

I don't have the answer of the top of my head, but phase noise of VCOs and PLLs is well documented. Perhaps "loop filter noise vco" or the like may help. On Mon, Aug 1, 2016 at 11:18 AM, Attila Kinali wrote: > On Mon, 01 Aug 2016 14:36:28 + > "Poul-Henning Kamp"

Re: [time-nuts] Syncing Tom's PICDivs to 1PPS

I think you will have to decided if you want both your xo (presumably 10 MHz) and PPS to be phase aligned to UTC. No matter which way you go you will have propagation delay across a clock divider. If you just want your PPS to be on phase, you can steer your xo. On Thu, Jul 21, 2016 at 12:11 AM,

Re: [time-nuts] GPS message jitter (preliminary results)

If your not bean counting for a commercial product you can take a look at particle filtering, its like a real-time monte-carlo simulation. The location estimate in NEMA is also heavily filtered and referenced to its utc time estimate (PPS). Conceivably could be filtered to a bandwidth of Fs/2,

Re: [time-nuts] GPS message jitter (was GPS for Nixie Clock)

I suppose it is one of those cases where, the GPS designers decided you shouldn't ever use the serial data for sub-second timing, and consequently spent no effort on serial latency and jitter. Most UARTs I have come across have been synthesized with a 16x baud clock and included flow control. It

Re: [time-nuts] GPS message jitter (was GPS for Nixie Clock)

I am happy to hear you issue was resolved. What I meant to say is the problem could also be mitigated using the UART's flow control, this could be done by the original GPS designers or by an end user if the CTS line is pined out. Gating the UART with a conservative delay, say 500 ms from the time

Re: [time-nuts] GPS message jitter (was GPS for Nixie Clock)

oad> On Mon, Jul 18, 2016 at 2:43 PM, jimlux <jim...@earthlink.net> wrote: > On 7/18/16 8:51 AM, Scott Stobbe wrote: > >> I suppose it is one of those cases where, the GPS designers decided you >> shouldn't ever use the serial data for sub-second timing, and consequentl

Re: [time-nuts] GPS message jitter (was GPS for Nixie Clock)

Sent: Monday, July 18, 2016 5:46 PM > Subject: Re: [time-nuts] GPS message jitter (was GPS for Nixie Clock) > > On 7/18/16 1:44 PM, Scott Stobbe wrote: > > Well, I suppose in the case of USB, the host hardware (consumer PC) is > not > > going to have any special hardware.

Re: [time-nuts] GPS message jitter (was GPS for Nixie Clock)

I can't speak for linux, but I have been bitten by FIFO watermark interrupts on micros before. If you set an interrupt for a 3/4 full FIFO, the last one or two characters will sit in the receive buffer and never trigger the RX interrupt. For a command -> response device which doesn't have a

Re: [time-nuts] GPS message jitter (was GPS for Nixie Clock)

A-0183 bus, do they report their best estimate of time to the nearest 10ms when the packet is sent? (since a PPS line isn't shared) On Tue, Jul 19, 2016 at 1:17 PM, Chris Albertson <albertson.ch...@gmail.com> wrote: > On Mon, Jul 18, 2016 at 10:44 AM, Scott Stobbe <scott.j.sto...@gmail.

Re: [time-nuts] GPS for Nixie Clock

It's fairly straight forward to build a 1 Hz NCO with a timer/counter block using your processor's LO. Threshold - Frequency, count - Phase. You can then DPLL to either PPS, Serial Data, or both. If your receiver drops its NAV or timing solution you still have "time". On Sun, Jul 10, 2016 at

Re: [time-nuts] OXCO Spurious Output at Line Frequencies

Unless your DUT is in a mu-metal enclosure, I wouldn't say observing the same results while battery powered provides any conclusive statement as to whether or not its the DUT. The terminals around a crystal are pretty high impedance at line frequencies. On Tue, Jul 12, 2016 at 6:44 AM, Martyn

Re: [time-nuts] How to properly characterize 32kHz oscillators manually and with a microcontroller?

For pulse counting, the timer hardware is the way to go. Setup a 16-bit timer clocked off your DUT. Then input capture on your PPS edge. This leaves you plenty of processor time for string formatting and other tasks you may wish to perform. If you do the decimation as post-processing on your PC

Re: [time-nuts] Safely getting the electrical length of a connected antenna feedline

Gate drivers are pretty zippy when you leave out the capacitive load of a power fet's gate. They are also available in 8 pin dip. On Monday, 8 August 2016, Bob Albert via time-nuts wrote: > Your comments on layout made me think again of how to implement these > projects.

Re: [time-nuts] Effect of EFC noise on phase noise

The broadband thermal noise at a circuit point with a cap is always kT/c On Monday, 1 August 2016, Bob Camp wrote: > Hi > > If you wire up all the possible circuits and check them all out … the > answer is that big C / small R wins. Big R gets you into resistor noise > issues >

Re: [time-nuts] Effect of EFC noise on phase noise

PM, Bob Camp <kb...@n1k.org> wrote: > HI > > Broadband is not where you run into the trouble on any of these circuits. > It’s > always what happens within a decade or two past cutoff or inside the pass > band. > > Bob > > > On Aug 1, 2016, at 4:50 PM, Scott St

Re: [time-nuts] Q/noise of Earth as an oscillator

I believe a phase noise plot deep into the uHz or lower would apply to the rotation rate of the earth. On Saturday, 23 July 2016, Hal Murray wrote: > > t...@leapsecond.com said: > > Earth is a very noisy, wandering, drifting, > incredibly-expensive-to-measure, > >

Re: [time-nuts] Switching transistors, current sources, nonidealties and noise

There are a plethora of ways to build up a current source. The nice thing about spice is you can start with a generalized model to see which way you need to go. For a bipolar current source (sampling current at the emitter) you are going to achieve a maximum output resistance of beta*ro with an

Re: [time-nuts] Switching transistors, current sources, nonidealties and noise

perform dramatically better. On Sat, Jul 2, 2016 at 1:04 PM, Attila Kinali <att...@kinali.ch> wrote: > On Fri, 1 Jul 2016 15:45:36 -0400 > Scott Stobbe <scott.j.sto...@gmail.com> wrote: > > > If you need higher output resistance you will have to move to a FET base

Re: [time-nuts] How to get PPS from ublox mini-PCI GPS to APU2 SoC serial port for ntpd

There should be no difference between COM2 or COM3/4, all four UARTs are likely hard logic. GPIO is just an alternate function for the COM3/4 pins. It will come down to what your are more comfortable with code or soldering. The NCT5104D is a QFP and its pins are reasonably accessible using 30 AWG

Re: [time-nuts] Sub-ps delay line

I would also advise you take a look at how well you can maintain your system impedance, say 50 Ohms. For example, I have seen about 100's ps phase difference on a 10 MHz reference, using one BNC female-female coupler versus another, a small part is due to TOF, but most of that is due to subtle

Re: [time-nuts] Dropbox is cool, but...

I've had similar results with LTSpice, by default it tosses the simulations results to the current working directory. Fortunately, you can tell LTSpice to use a specific temp folder for simulation results. On Sun, Feb 5, 2017 at 7:42 PM, Didier Juges wrote: > Yes, I noticed

Re: [time-nuts] purpose of time of day display units

There is a lot to be said about a tool that just works. In the advent of a piece of gear failing whether that be a firmware bug or a cooling fan, or more severe, having a known diagnostic tool during that time is priceless (well maybe not priceless but extremely nice to have). On Sun, Jan 22,

Re: [time-nuts] Thermal effects on cables

A google search for digiwave turned up cheap coax at walmart. I don't know how well copper clad steel holds up in the kHz, low MHz. On Mon, Jan 23, 2017 at 5:01 PM, Bob Camp wrote: > Hi > > Back a long time ago the people I was working with spent time looking > at the impedance

Re: [time-nuts] Distribution amplifier (again!) - now mostly ok but has gain peaking

Nice project. The gain peaking is more than likely from your high speed opamp. Parasitic capacitance on the inverting terminal from routing and the input capacitance of the opamp itself, adds another pole to your opamps loopgain, burning phase margin. A small compensation cap across the top leg

Re: [time-nuts] HP5328A + NI GPIB-ENET/1000

If your counter is showing up in the NI device tree, you should be pretty close to getting it working. I haven't used a 5328A, but I suspect the command you have shown above is sample code for a basic program, the actual HPIB command may just be a 'T'. On Thu, Feb 23, 2017 at 1:37 AM, James

[time-nuts] Vintage Frequency Measurement

I was inspired recently coming across a Lampkin 105 frequency meter, as to how frequency measurement was done before counters. Certainly zero-beating a dial calibrated oscillator, would be one approach. Is there a standout methodology or instrument predating counters?

Re: [time-nuts] Vintage Frequency Measurement

On Mon, Feb 13, 2017 at 6:41 PM, Bob Camp wrote: > > > I think what you would find is that it *is* a fairly normal AT cut and the > data book > that came with the instrument plotted out the data for the specific > crystal in > the device. The usable temperature range was fairly

Re: [time-nuts] ``direct'' RS-232 vs. RS-232 via USB vs. PPS decoding cards

Something like this would make a great NTP server. https://www.digikey.com/products/en?keywords=P0286-ND Too bad they didn't include a PTP 1588 capable PHY... On Tue, Feb 14, 2017 at 12:33 PM, Chris Albertson wrote: > Here is a something that could work. It has a

Re: [time-nuts] Vintage Frequency Measurement

On Sun, Feb 12, 2017 at 8:39 AM, Dan Rae <dan...@verizon.net> wrote: > On 2/11/2017 10:08 PM, Scott Stobbe wrote: > >> I was inspired recently coming across a Lampkin 105 frequency meter, as to >> how frequency measurement was done before counters. >> >> Cert

Re: [time-nuts] Vintage Frequency Measurement

Neat bit of kit. Was it common to get IMD with harmonics out of the vibrator power supply, and end up on tuning in on the wrong frequency? On Wed, Feb 15, 2017 at 2:28 AM, Robert Atkinson via time-nuts < time-nuts@febo.com> wrote: > Hi,Sorry if I caused confusion by calling the SCR/BC221 a

Re: [time-nuts] time-nuts Digest, Vol 150, Issue 36

Temperature sensor (Perry Sandeen) > >> 12. Who has a hm H Maser? (Perry Sandeen) > >> 13. Who has a hm H Maser? (Perry Sandeen) > >> 14. TICC update? (Scott Newell) > >> 15. R

Re: [time-nuts] Low CostTemperature sensor

Thermometry based on Diode leakage current wouldn't be impossible I suppose, you might loose some hair in the process. The signal levels on the opamp are goofed too. On Tue, Jan 17, 2017 at 4:19 AM Charles Steinmetz wrote: > Tom wrote: > > > > > That article has a major

Re: [time-nuts] Thunderbolt Harmonics

Harmonic traps are another avenue to explore since the frequency is "fixed" at well below ppm. Which leaves the fundamental untouched. On Wed, Jan 18, 2017 at 5:21 AM, Charles Steinmetz wrote: > Rhys wrote: > > I was looking at the output of my Trimble Thunderbolt GPSDO

Re: [time-nuts] 10MHz to 25MHz

Wouldn't crystal drive level be one of the important specifications for far out phase noise? On Thu, Jan 19, 2017 at 1:33 PM, Bob Camp wrote: > HI > > A lot of your evaluation of the term “better” will depend on your intended > use. One of the limits on phase noise > is the

Re: [time-nuts] 10MHz to 25MHz

, Jan 19, 2017 at 7:06 PM Bob Camp <kb...@n1k.org> wrote: > Hi > > > > > > > On Jan 19, 2017, at 3:03 PM, Scott Stobbe <scott.j.sto...@gmail.com> > wrote: > > > > > > Wouldn't crystal drive level be one of the important specifications for &

Re: [time-nuts] time transfer over wifi

Here is a ti app note with timestamping hardware wl8 but ordinary ap's with no special protocol just timestamping the beacon frame. http://www.ti.com/lit/an/swaa162a/swaa162a.pdf On Sun, Jan 15, 2017 at 10:06 AM jimlux wrote: > Returning to the OP > > "A TimeSync

Re: [time-nuts] time transfer over wifi

Pretty much every wifi transceiver is adc sampled so the frames are "timestamped", but the adc sample time may not get pushed up. The rtt/tof for the large umbrella of localization applications, I would imagine will be impented even farther back in the rx chain. On Sun, Jan 15, 2017 at 11:42 AM

Re: [time-nuts] How to get PPS from ublox mini-PCI GPS to APU2 SoC serial port for ntpd

wrote: > Could another way be to cut out the mini-pci interface like > http://galeria.tech-blog.pl/U-blox_PCI-5S_GPS/U-blox_PCI-5S_ > GPS_10.jpg.html though I'm not sure if he's driving it via serial? > > > -Original Message- > From: time-nuts [mailto:time-nuts-boun...@f

Re: [time-nuts] Hobbyist grade or homebrew temperature testing chamber?

The bargain price mini coolers are often peltier cooled, they appear to fall under the marketing term "thermoelectric mini-fridge". I can't think of a project name, but I'm sure I've seen this done before using a mini fridge. On Monday, 5 September 2016, Richard (Rick) Karlquist

Re: [time-nuts] Hobbyist grade or homebrew temperature testing chamber?

-20 mA to the 1 - 10 VDC analog input of an LED driver (there are a plethora available "Meanwell led driver" is one that comes to mind). On Tue, Sep 6, 2016 at 12:05 AM, jimlux <jim...@earthlink.net> wrote: > On 9/5/16 8:52 PM, Scott Stobbe wrote: > >> The bargain

Re: [time-nuts] Lady Heather's Tbolt oscillator auto-tune function

Interesting discussion about startup. At startup the phase error of the synthesized PPS is +- 0.5 s. Is this coarsely set to the nearest ocxo cycle once gps time is established (would make sense to do it this way), or is the half second recovered steering the ocxo? On Tuesday, 13 September 2016,

[time-nuts] Lady Heather's Tbolt oscillator auto-tune function

Pardon my lack of knowledge regarding Lady Heather, what is the x-axis scale? I assumed the text line above the plot is the various y-axis scales. This is good data. Thanks On Tuesday, 13 September 2016, Mark Sims > wrote: >

Re: [time-nuts] Lady Heather's Tbolt oscillator auto-tune function

ing the counter that generates the PPS. At a > 1 ppm frequency > offset, it could take 500,000 seconds to steer it in with the OCXO. It > unlikely people would wait > for over a week for the PPS to line up …. > > Bob > > > On Sep 13, 2016, at 5:58 PM, Scott Stobbe <sco

[time-nuts] Lady Heather's Tbolt oscillator auto-tune function

se of > jerking the frequency around a lot. A loose (large) damping does not > change the > frequency much, but the time wanders quite a bit. > > Simply put: There is no free lunch. > > Bob > > > On Sep 13, 2016, at 9:01 PM, Scott Stobbe <scott.j.sto...@gmail.com> &

Re: [time-nuts] Normal operating specs of a Morion MV89?

Your oscilloscope fft is plotting single-side amplitude spectrum in V/rtHz (dBV/rtHz), this is in contrast to a spectrum analyzer which plots power spectral density W/Hz or (dBm/Hz). So -2.17 dBv is 10^(-2.17/20) = 0.779 Vrms comparing this to your Vpk-pk measurement 2.3 / 2 / sqrt(2) = 0.813

Re: [time-nuts] Normal operating specs of a Morion MV89?

If you used a 10x probe (10 Meg || 10-15 pF) you may have a pretty weak output, but if you could drive a meter of coax or a 1x probe to 800 mVrms at 10 MHz your probably not too far off spec. 100 pF at 10 MHz is 160 Ohms. On Wed, Sep 28, 2016 at 12:39 PM, Tim Lister wrote:

Re: [time-nuts] ADC sample voting algorithm?

It sounds like once in awhile your sampling something else too. Ground bounce of a 10 MHz buffer, or something coupling onto your phase detector, or running your adc at the edge of a timing spec? How large would the outlier be in mV? On Wednesday, 5 October 2016, Nick Sayer via time-nuts

Re: [time-nuts] AC line distortion [Was: HP 105B Battery, the saga continues]

Considering some signal generators will have 1% (-40dBc) distortion with a 5k - 10k price tag, your 1% is not to bad. On Mon, Oct 3, 2016 at 8:52 PM, Jeremy Nichols wrote: > As an experiment, I bought an AIMS sine-wave inverter for the 105B Quartz > Oscillator. The inverter

Re: [time-nuts] Prologix USB-GPIB Controller

An example which likely has similar volume to the Prologix is the saleae logic analyzer, google "saleae clone". On Fri, Oct 7, 2016 at 9:13 PM, Hal Murray wrote: > > They get counterfeited a *lot*. > > Is that true for relatively obscure things like the Prologix GPIB >

Re: [time-nuts] TimeLab

FWIW, I have only tried timelab reading a live ascii log file. On Sunday, 9 October 2016, Magnus Danielson wrote: > Which removes the real-time processing benefit of using TimeLab in the > first place. > > What I propose is not too complex to do. > > Cheers, > Magnus

Re: [time-nuts] 53132A triggering

For a low duty cycle pulse, the ac coupled signal will be approximately the same as if it were dc coupled. Not sure I follow what you mean. There will be only one rising edge for a narrow pulse ac coupled, as the falling edge occurs much quicker than the HPF time constant. On Friday, 16 September

Re: [time-nuts] Lucent RFTFm-II-XO

You may even be lucky enough to see brief periods of phase reversal on some of the amplifiers on the input chain, adding more edges. On Thu, Sep 22, 2016 at 3:47 PM, Charles Steinmetz wrote: > Bill wrote: > > If you could, would you see if you can take the pps out of

Re: [time-nuts] Lady Heather's plotting functions

The joys of a small display, why couldn't I see that. Many thanks Mark & Peter. Soon to be the emac's of gpsdo's (in the good, can do anything sense) well done. On Wed, Sep 14, 2016 at 12:27 AM, Mark Sims wrote: > You can set the view interval to any value with the "V"

Re: [time-nuts] 53132A triggering

me issues. On Sat, Sep 17, 2016 at 10:28 AM, Bob Camp <kb...@n1k.org> wrote: > Hi > > Set it up on your 53132 and see what happens … > > Bob > > > On Sep 16, 2016, at 8:35 PM, Scott Stobbe <scott.j.sto...@gmail.com> > wrote: > > > > For a low d

Re: [time-nuts] How to get PPS from ublox mini-PCI GPS to APU2 SoC serial port for ntpd

The mini-PCI Express Card specification includes quite a bit more than just a single PCI-Express lane, there is also provisions for I2C (smbus), USB, LEDs, SIM, etc... While without looking a the physical card or specification I can't be certain, but I highly doubt it implements a PCI-Express

Re: [time-nuts] Normal operating specs of a Morion MV89?

pe screen for comparison. (I haven't been able to > get a screen capture yet as I need to find a small enough capacity USB > key that will be supported by the scope) > > Tim > > > > > Otherwise, you can open up the can and replace the output chip capacitor. > &g

Re: [time-nuts] notch filter for close in phase noise measurement

What's the loaded Q of such a notch filter? 50 dB 100 Hz off of 10 MHz sounds like a pretty lousy Q. On Sunday, 2 October 2016, Bob Camp wrote: > Hi > > The issue is *not* about notch filters and if they are useful. The gotcha > is > that they are mainly useful far removed from

Re: [time-nuts] Normal operating specs of a Morion MV89?

. On Friday, 30 September 2016, Tim Lister <lister...@gmail.com> wrote: > On Wed, Sep 28, 2016 at 3:30 PM, Scott Stobbe <scott.j.sto...@gmail.com > <javascript:;>> wrote: > > You are certainly no where near -40 dBm into 50 ohms as the blog Bryan > > posted above. Your s

Re: [time-nuts] Normal operating specs of a Morion MV89?

I think you have mistaken the tilde symbol as a negative sign. Tim's 11 dBm is into the pad. 7 dBm +- 2 dB into 50 ohms is the spec for the mv89 no? On Saturday, 1 October 2016, Bob Camp <kb...@n1k.org> wrote: > HI > > > On Oct 1, 2016, at 4:08 PM, Scott Stobbe <sco

Re: [time-nuts] Temp/Humidity control systems?

I have always wondered how large the market for those hydroponic/indoor gardening stores really is, maybe they have something to fit the bill. On Wed, Oct 26, 2016 at 11:59 AM, John Ackermann N8UR wrote: > I may have the opportunity to build a small "clock room" and am >

Re: [time-nuts] Opening an Isotemp OCXO

The OCXO82-59 datasheet lists 12V supply, 5V clock out, could also be a blown regulator in your ocxo, if it is indeed a 12v model. On Friday, 28 October 2016, Poul-Henning Kamp wrote: > > In message <10a3ea7d-37f0-51bc-2470-35645d767...@comcast.net >

Re: [time-nuts] Opening an Isotemp OCXO

Could also be a quirk about the 74S30 that gives it better phase noise over a basic buffer. On Friday, 28 October 2016, jimlux <jim...@earthlink.net> wrote: > On 10/28/16 9:13 AM, Scott Stobbe wrote: > >> The OCXO82-59 datasheet lists 12V supply, 5V clock out, could also be a

Re: [time-nuts] Opening an Isotemp OCXO

I wounder if originally the designer was hoping to use all 8 wire or'd inputs to lower the input referred noise during midscale transition. Then backed out later for some reason. On Fri, Oct 28, 2016 at 1:03 PM, Scott Stobbe <scott.j.sto...@gmail.com> wrote: > Could also be a qu

Re: [time-nuts] our favorite topics

I found Frerking's "Crystal Oscillator Design and Temperature Compensation" to be a fruitful read. It's free on the archive, https://archive.org/details/CrystalOscillatorDesignTemperatureCompensation . Are there any recommendations for one or more book(s) that are definitely worth skimming

Re: [time-nuts] Thermal impact on OCXO

gt; with such arcane matters as holdover, aging, and generating the time from > the OCXO. The learning curve has been a bit steep. > > Bob > > - > AE6RV.com > > GFS GPSDO list: > groups.yahoo.com/

Re: [time-nuts] Thermal impact on OCXO

Typo, "Aging [PPM]" should read "Aging [PPB]". On Mon, Nov 7, 2016 at 10:34 AM, Scott Stobbe <scott.j.sto...@gmail.com> wrote: > Here is a sample data point taken from http://tycho.usno.navy.mil/ > ptti/1987papers/Vol%2019_16.pdf; the first that showed up on a go

Re: [time-nuts] Thermal impact on OCXO

would be a candidate for the symptoms of aging. > > Bob > > > - > AE6RV.com > > GFS GPSDO list: > groups.yahoo.com/neo/groups/GFS-GPSDOs/info > > > -- > *From:* Scott Stobbe <scott.j.sto...@gmail.com> > *To:* Bob Stewar

Re: [time-nuts] Man with too many clocks.

I'm not sure if there is a reason counters don't let you digitally calibrate beyond that, the 10 MHz ref out on the rear panel would still be out of cal. On Fri, Nov 4, 2016 at 1:48 PM, Bob Camp wrote: > Hi > > The only practical way to set the 10811 or 10544 is with a >= 10 turn

Re: [time-nuts] I love the smell of tantalum in the morning

I would not recommend purchasing soldering tweezers without trying them first. They are not easy to control solder application when mounting a component. I do really like the Weller rt7 knife tip. On Sunday, 6 November 2016, Adrian Godwin wrote: > SMD parts aren't going

Re: [time-nuts] Thermal impact on OCXO

Sounds like you already realized this. Phase is the integral of frequency and the derivative of phase (phase rate) is frequency. So if you go from nominal frequency - slow - nominal or equivalently nominal frequency - fast - nominal the phase integrates up/down. It would be a little more

Re: [time-nuts] I love the smell of tantalum in the morning

In the case of the rt7 (or knife soldering tips for other brands) you get a fine point that easily handles 30-32 awg wire, and the edge of the tip is a little over 100 thou long, so for parts 0805 and smaller you just lay the edge along the side of the component and heat both pads and swipe it to

Re: [time-nuts] HP 5275A

You could try heating the transistor and bushing then give the to5 a shot of cold spray or supper duster hoping it will shrink enough to slide out. On Sunday, 6 November 2016, Adrian Godwin wrote: > Slightly off-topic, as this is a general repair question. But it's a TIC. >

Re: [time-nuts] How to get PPS from ublox mini-PCI GPS to APU2 SoC serial port for ntpd

Just make sure you get a board with more than one Rx/Tx pair, unless you are happy with two boards; one for Rx/Tx and one for PPS. On Wed, Nov 9, 2016 at 2:08 AM, Hal Murray wrote: > > g...@rellim.com said: > > Who cares if the PPS is inverted? > > Good point. I wasn't

Re: [time-nuts] How to get PPS from ublox mini-PCI GPS to APU2 SoC serial port for ntpd

FWIW, the 16450 uart can interrupt on any modem line change, whether it be rising or falling. On Wed, Nov 9, 2016 at 11:41 AM, Chris Albertson wrote: > On Tue, Nov 8, 2016 at 11:08 PM, Hal Murray > wrote: > > > > > g...@rellim.com said: > > >

Re: [time-nuts] Thermal impact on OCXO

C string that might be controversial, > but I don't see that it would be a candidate for the symptoms of aging. > > > > Bob > > --------- > > AE6RV.com > > > > GFS GPSDO list: > > groups.

Re: [time-nuts] Need some wisdom from the cesium beam tube gurus out there

If you want sub degree precision, you will need to make your connections to dissimilar metals on an isothermal boundary, a terminal block is better than clips in free air. On Fri, Nov 11, 2016 at 8:28 AM, Bob Camp wrote: > Hi > > > On Nov 11, 2016, at 8:02 AM, jimlux

Re: [time-nuts] How to get PPS from ublox mini-PCI GPS to APU2 SoC serial port for ntpd

When 1PPS is implemented as a time mark signal narrow width (versus 1 Hz 50% duty cycle) and you time stamp both edges, you can always tell which is supposed to be the leading edge. Either the assert and deassert are close together in the correct case or far apart when using incorrect polarity.

Re: [time-nuts] I love the smell of tantalum in the morning

For through hole parts sure, but I would not recommend that on SMD parts, the copper foil of a little pad is pretty easy to tear off and it's a royal pain if you have to mount a device missing some of its landing pads. On Sat, Nov 5, 2016 at 4:37 PM, Tom Miller wrote:

Re: [time-nuts] Thermal impact on OCXO

ut 4.5PPT? > > Bob > > - > AE6RV.com > > GFS GPSDO list: > groups.yahoo.com/neo/groups/GFS-GPSDOs/info > > > > > -- > *From:* Scott Stobbe <scott.j.sto...@gmail.com> > *To:* Bob Stewart <b...@evoria.net>; Discussion of preci

Re: [time-nuts] Thermal impact on OCXO

I think that's a nice plot, it looks like you have stepped 160 LSB over 7 days or roughly 1 LSB per hour. With a 20bit dac you are trimming maybe 1 ppt/LSB to 4 ppt/LSB? In allan devation terms, the case of 1ppt/LSB, solely due to drift, you're at 1E-12 at 3600*sqrt(2) = 5000 s, in the case of

Re: [time-nuts] Thermal impact on OCXO

Another nice plot! It looks like after 2am you see temperature swings of 1.5 degF roughly every 30 minutes? Correspondingly, the EFC line which is nominally ~2.8vdc sees swings of +-50 uV? On Monday, 7 November 2016, Bob Stewart wrote: > Hi guys, > First of all, thanks for the

Re: [time-nuts] Anybody want a Thunderbolt power supply?

olts on the > -12V line. > > Bob > > > On Oct 22, 2016, at 10:24 AM, Scott Stobbe <scott.j.sto...@gmail.com> > wrote: > > > > It all depends what the -12V rail is for, some have said it directly > > references the EFC dac. I would hope an ocxo would hav

Re: [time-nuts] Anybody want a Thunderbolt power supply?

t; The +12 goes straight to the OCXO. All OCXO’s have a voltage sensitivity. > That sensitivity is much higher than voltage sensitivity is much higher > than > what you see on the other two supply pins. > > Bob > > > On Oct 21, 2016, at 11:06 PM, Scott Stobbe <scott.

Re: [time-nuts] Anybody want a Thunderbolt power supply?

es from the TBolt board and not from the > OCXO. > It is not in any way connected to the -12 V supply line. > > Bob > > > > > On Oct 22, 2016, at 12:41 PM, Scott Stobbe <scott.j.sto...@gmail.com > <javascript:;>> wrote: > > > > Bob, this is good data an

Re: [time-nuts] Anybody want a Thunderbolt power supply?

al 7912 fed by a normal supply will not produce a noticeable > degradation > in phase nose on the TBolt. Putting an un-filtered switcher on any of the > lines is going > to get you noise on the common ground that *will* come through. > > Bob > > > > On Oct 22, 2016, at

Re: [time-nuts] Anybody want a Thunderbolt power supply?

I'm sure I have some 7805s lying around, maybe a 7812/7912. I'm interested to see the 1/f noise of a classic regulator, what load current do you expect? I can bias a 7805 for the same load and measure the 0.1 to 10 Hz noise. Also if you have a digital scope without a very good builtin FFT, octave

Re: [time-nuts] measuring noise of power supplies (was: For those that insist on using switching power supplies)

Reinforcing your first point. It is also worth noting that the sweet spot for switching regulators is about the same frequency as the AM band. Cars have had both switching regulators and AM radio for a while now. On Sun, Oct 16, 2016 at 12:06 AM, Perry Sandeen via time-nuts < time-nuts@febo.com>

Re: [time-nuts] 1PPS to 32.768 khz

If the heart of your clock is a micro, you may be able to reset the processor and set the time once a second fastest enough not to have any visual artifacts. Even if you have a perfect 32.768 kHz clock you still have to set the phase (time) manually and deal with DST, leap seconds, and power

Re: [time-nuts] Anybody want a Thunderbolt power supply?

... On Friday, 21 October 2016, Bob Camp <kb...@n1k.org> wrote: > Hi > > > On Oct 21, 2016, at 7:44 PM, Scott Stobbe <scott.j.sto...@gmail.com > <javascript:;>> wrote: > > > > A little more data on the 7912. > > > > The first plot shows the

  1   2   >