Re: [time-nuts] PLL performance?

Yes, this is not a spring powered clock with gears. The pendulum will be impulsed every N swings by a small weight. (Not yet sure what N will be.) Scott On Thursday, March 23, 2017 11:34:44 AM EDT paul swed wrote: > Hello to the group quite late to the discussion. Pretty interesting. > But I

Re: [time-nuts] PLL performance?

Hello to the group quite late to the discussion. Pretty interesting. But I assume the drive for the pendulum is some impulse. Not the old mechanical clock with a spring for power. Regards Paul WB8TSL On Wed, Mar 22, 2017 at 7:48 PM, David Scott Coburn wrote: > I will not

Re: [time-nuts] PLL performance?

I will not be using an off-the-shelf optical interrupter type sensor for this. I have designed a custom IR LED -> IR photodiode unit which will have a flag that blocks half of the IR signal when the pendulum is stopped, and the motion of the pendulum will modulate this 50% signal from about

Re: [time-nuts] PLL performance?

Hi As others have pointed out, a control loop at 100 seconds is more a gain spec than an R/C time constant spec. The real issue is that you should have an integrator on the loop and that *is* an R/C sort of thing. It’s also likely to have a much longer time constant than the magic number for

Re: [time-nuts] PLL performance?

att...@kinali.ch said: > There have been a couple of discussions about doing GPSDOs using only analog > components in the past. People fare more knowledgable than me have commented > there on what the challenges would be and how to solve them. So I recommend > to go through the archives and look

Re: [time-nuts] PLL performance?

Neat Project. I don't know if it will come up for you but optical or hall rotary encoders are notorious for jitter. While a generic IC comparator may have an open loop-gain of 100 dB, creating the mechanical equivalent is not so easy. Hall/optical have a softer switch on/off curve. Depending what

Re: [time-nuts] PLL performance?

On Tue, 21 Mar 2017 21:10:19 -0400 David Scott Coburn wrote: > > What information are you looking for? > > I was curious if anyone else has tried to do a PLL with two 0.5 Hz signals. > Does not seem like a particularly popular pastime! I did find a few articles >

Re: [time-nuts] PLL performance?

The loop filter does have a very low bandwidth, of the order you mentioned. The lock time is surprisingly quick, but one man's pocket change may be another man's fortune I use a lag-lead filter with the PC2 comparator. It begins to 'track' after a minute or so. >From a cold start there

Re: [time-nuts] PLL performance?

ai.egrps...@gmail.com> > To: "Discussion of precise time and frequency measurement" > <time-nuts@febo.com> Sent: Tuesday, March 21, 2017 12:23 AM > Subject: Re: [time-nuts] PLL performance? > > > Second file successfully opened in Irfanview. > &

Re: [time-nuts] PLL performance?

On Tuesday, March 21, 2017 12:22:46 PM EDT Tom Van Baak wrote: > Hi Scott, > > That's a nice project. > > Combining quartz and pendulum like that is essentially how a GPSDO works. In > your case, instead of a 10 MHz oscillator you have a 1 MHz oscillator and > instead of 1PPS you have 1/2 PPS.

Re: [time-nuts] PLL performance?

Ack! Sorry for the questionable PDF file. It was generated by gnuplot on my Linux system. I see that Tom has posted a gif of the image, so I won't duplicate it. Cheers, Scott On Monday, March 20, 2017 10:36:05 PM EDT Bill Byrom wrote: > Hi, Scott. I rarely post here, but just noticed your

Re: [time-nuts] PLL performance?

On Tuesday, March 21, 2017 12:26:59 PM EDT Attila Kinali wrote: > Moin, > > On Mon, 20 Mar 2017 21:07:03 -0400 > > David Scott Coburn wrote: > > I have built and tested a PLL circuit that will be used to generate a 1 > > MHz > > signal locked to a 0.5 HZ signal from a

Re: [time-nuts] PLL performance?

Hi Scott, That's a nice project. Combining quartz and pendulum like that is essentially how a GPSDO works. In your case, instead of a 10 MHz oscillator you have a 1 MHz oscillator and instead of 1PPS you have 1/2 PPS. Whether you use an analog loop or a digital loop there are dozens of

Re: [time-nuts] PLL performance?

To get your loop to lock and keep phase noise down the loop filter would need a bandwidth of .05 Hz or less. That would mean long lock times. Very long lock times.  Engineering is the art of making what you want from what you can get at a profit. I like Polywell Fusion. On Tuesday,

Re: [time-nuts] PLL performance?

Moin, On Mon, 20 Mar 2017 21:07:03 -0400 David Scott Coburn wrote: > I have built and tested a PLL circuit that will be used to generate a 1 MHz > signal locked to a 0.5 HZ signal from a pendulum. (Details available upon > request.) [...] > I tested this by feeding the

Re: [time-nuts] PLL performance?

Tuesday, March 21, 2017 12:23 AM Subject: Re: [time-nuts] PLL performance? > Second file successfully opened in Irfanview. > > Three other PDF readers, including Adobe, could not open it. > > Andy ___ time-nuts mailing list --

Re: [time-nuts] PLL performance?

Second file successfully opened in Irfanview. Three other PDF readers, including Adobe, could not open it. Andy ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow

Re: [time-nuts] PLL performance?

Hi, Scott. I rarely post here, but just noticed your post. I can open the "PLL0.pdf" file, but the other files appears to be corrupted. Adobe Acrobat Reader thinks it's not really a PDF file or it's corrupted. I'm not ready to comment on the expected results yet, and would like to see the

Re: [time-nuts] PLL performance?

Hi. I did a 15728640Hz signal locked to a 7680Hz reference using a 74hct9046. It was ugly (I mean, individual trimming of the resistors... I assembled 20 boards). Circuit behaves more like a FLL than a PLL (if you look at both with an scope they never quite locks to each other), but it works