Re: [time-nuts] GPSDO and oscillator steering - EFC vs DDS schemes?

On 12/8/15 3:31 PM, Bob Camp wrote: Hi Let’s see: EFC uses reference out of the OCXO. EFC comes on the OCXO at no added cost. 16 bit DAC costs ~$2 to $5 Total cost for EFC setup $2 to $5. Net result is a system with spurs that are how ever far down you wish them to be. (It’s all about

Re: [time-nuts] GPSDO and oscillator steering - EFC vs DDS schemes?

In message <56675da0.4050...@rubidium.dyndns.org>, Magnus Danielson writes: >> So, what did I miss? Why do people use DAC-EFC control instead of >> the DDS scheme? > >The main reason I would say is habbits, people have habbits and stick to >them. And I think right after that comes the

Re: [time-nuts] GPSDO and oscillator steering - EFC vs DDS schemes?

God eftermiddag, On Tue, 8 Dec 2015 23:45:52 +0100 Magnus Danielson wrote: > If you would setup essentially a micro-stepper design, such as those > being used for cesium and hydrogen masers, but maybe adapted to a > hobbyist needs and with straight-forward way of

[time-nuts] Phase microstepper designs?

Moin, I just tried to figure out how phase microsteppers are usually build, but, beside the time-nuts discussion from 10 years ago and US patents US4358741 and US4417352 my search turned out empty. I am pretty sure that I used the wrong search terms and there should be lots of documentation out

Re: [time-nuts] GPSDO and oscillator steering - EFC vs DDS schemes?

Hi > On Dec 8, 2015, at 11:20 PM, Jim Lux wrote: > > On 12/8/15 3:31 PM, Bob Camp wrote: >> Hi >> >> Let’s see: >> >> EFC uses reference out of the OCXO. >> EFC comes on the OCXO at no added cost. >> 16 bit DAC costs ~$2 to $5 >> >> Total cost for EFC setup $2 to $5.

Re: [time-nuts] GPSDO and oscillator steering - EFC vs DDS schemes?

On 12/9/15 4:37 AM, Bob Camp wrote: Hi On Dec 8, 2015, at 11:20 PM, Jim Lux wrote: On 12/8/15 3:31 PM, Bob Camp wrote: Hi Let’s see: EFC uses reference out of the OCXO. EFC comes on the OCXO at no added cost. 16 bit DAC costs ~$2 to $5 Total cost for EFC setup $2 to

Re: [time-nuts] Phase microstepper designs?

Do you mean delay-generators for 1PPS? Or a finely-tunable frequency synthesizer? For 1PPS, the fine-delay FMC card might be worth a look: http://www.ohwr.org/projects/fmc-delay-1ns-8cha/wiki afaik it works by first time-stamping the input pulse, then delaying the output with an integer number

Re: [time-nuts] Phase microstepper designs?

> Are you aware of some redeeming value that phase microsteppers > have that would make us want to investigate them? Am I > being too harsh on them? Maybe you can champion them and they > will make a come back :-) > > Rick Karlquist N6RK A phase microstepper is useful with many older Rb and

Re: [time-nuts] Phase microstepper designs?

Hi Attila: Once you find a patent you can then search on the class number for very similar patents. See the links under "Handy External Links:" http://www.prc68.com/I/Learning.shtml Quick allows searching for a class number or other fields (but not the text of the patent). PS Sunnyvale has a

Re: [time-nuts] GPSDO and oscillator steering - EFC vs DDS schemes?

A friend and I have been messing with a DDS replacement for the VFO in older radios. The odds runs between 5 and 5.5 MHz. There are some mixers that generate the final LO frequency. We found many many birdies (caused by spurs for the non-hams) over the tuning ranges. We had to put in a lo-pass

Re: [time-nuts] Phase microstepper designs?

> Moin, > > I just tried to figure out how phase microsteppers are usually build, > but, beside the time-nuts discussion from 10 years ago and US patents > US4358741 and US4417352 my search turned out empty. I am pretty sure > that I used the wrong search terms and there should be lots of

Re: [time-nuts] GPSDO and oscillator steering - EFC vs DDS schemes?

Don, DDSes used to be very crude in terms of spurs. However, things have improved significantly and some of the chips you can get now is pretty impressive. It has even inspired some significantly different radio designs in the ham world. As for filters, yes, they can vary delay with

Re: [time-nuts] Phase microstepper designs?

Hi > On Dec 9, 2015, at 12:34 PM, Tom Van Baak wrote: > >> Are you aware of some redeeming value that phase microsteppers >> have that would make us want to investigate them? Am I >> being too harsh on them? Maybe you can champion them and they >> will make a come back

Re: [time-nuts] Phase microstepper designs?

Hi, Vremya also have such boxes. The current one, VCH-317, goes under the name "Real-Time Atomic Clock Combiner" which may not give you the initial association of it being a micro-stepper. I have read the manual for an older box, or at least an older description, which included a nice

Re: [time-nuts] GPSDO and oscillator steering - EFC vs DDS schemes?

In message <566883d1.6050...@rubidium.dyndns.org>, Magnus Danielson writes: >Indeed. As any engineering time estimate, you need to multiply with pi. >At work, we engineers divide our estimates with pi before giving it to >the project managers, as they will multiply with pi before

Re: [time-nuts] GPSDO and oscillator steering - EFC vs DDS schemes?

Hi > On Dec 9, 2015, at 9:34 AM, Jim Lux wrote: > > On 12/9/15 4:37 AM, Bob Camp wrote: >> Hi >> >>> On Dec 8, 2015, at 11:20 PM, Jim Lux wrote: >>> >>> On 12/8/15 3:31 PM, Bob Camp wrote: Hi Let’s see: EFC uses reference

Re: [time-nuts] GPSDO and oscillator steering - EFC vs DDS schemes?

God kväll, On 12/09/2015 11:47 AM, Attila Kinali wrote: God eftermiddag, On Tue, 8 Dec 2015 23:45:52 +0100 Magnus Danielson wrote: If you would setup essentially a micro-stepper design, such as those being used for cesium and hydrogen masers, but maybe adapted

Re: [time-nuts] GPSDO and oscillator steering - EFC vs DDS schemes?

Poul-Henning, On 12/09/2015 09:24 AM, Poul-Henning Kamp wrote: In message <56675da0.4050...@rubidium.dyndns.org>, Magnus Danielson writes: So, what did I miss? Why do people use DAC-EFC control instead of the DDS scheme? The main reason I would say is habbits, people have habbits

Re: [time-nuts] Phase microstepper designs?

it is not a hint, for what you asked, but if you add a DC voltage to the output of the phase detector in an analog PLL the VCO phase could be adjusted, similarly if you add a constants to the input data of a phase accumulator of the NCO you could adjust the phase of the NCO but be aware, the

Re: [time-nuts] GPSDO and oscillator steering - EFC vs DDS schemes?

Some of the suggestions offered here are incorporated in the FE 205/405/505. We have done extensive work using a 405 with very good results. Tom did some tests on the 406 and we traced issues back to the temperature control. We disabled it and continue to have an excellent GPSDO. Tests are

Re: [time-nuts] Phase microstepper designs?

On 12/9/2015 2:26 AM, Attila Kinali wrote: Moin, I just tried to figure out how phase microsteppers are usually build, but, beside the time-nuts discussion from 10 years ago and US patents US4358741 and US4417352 my search turned out empty. I am pretty sure that I used the wrong search terms