[time-nuts] Generating a solid PPS from 10Mhz source - finetuned start

Hi Guys, Le mercredi 13 janvier 2016 à 09:22 +, Jerome Blaha a écrit : > Hey Guys, > > Is there an easy circuit to build that can consistently deliver a 1 > PPS from a 10MHz source with excellent resolution and > repeatability?  My first application is to test different 10MHz > oscillators

Re: [time-nuts] Generating a solid PPS from 10Mhz source - finetuned start

Hi > On Jan 25, 2016, at 8:55 AM, Xavier Bestel wrote: > > Hi Guys, > > Le mercredi 13 janvier 2016 à 09:22 +, Jerome Blaha a écrit : >> Hey Guys, >> >> Is there an easy circuit to build that can consistently deliver a 1 >> PPS from a 10MHz source with excellent

Re: [time-nuts] Generating a solid PPS from 10Mhz source

On Wed, 20 Jan 2016 17:56:31 -0500 Bob Camp wrote: > > Interestingly, some were close to 0ps, for which > > we have no good explanation. > > The explanation is fairly simple, you have a clock and a “data pulse” > flying down the delay / carry chain. With an ASIC you could make

Re: [time-nuts] Generating a solid PPS from 10Mhz source

Hi > On Jan 21, 2016, at 5:48 AM, Attila Kinali wrote: > > On Wed, 20 Jan 2016 17:56:31 -0500 > Bob Camp wrote: > >>> Interestingly, some were close to 0ps, for which >>> we have no good explanation. >> >> The explanation is fairly simple, you have a clock

Re: [time-nuts] Generating a solid PPS from 10Mhz source

rd RC oscillator as > driven by the OCXO. > > Bob > > > > > On Wed, 1/20/16, Poul-Henning Kamp <p...@phk.freebsd.dk> wrote: > > Subject: Re: [time-nuts] Generating a solid PPS from 10Mhz source > To: "Disc

Re: [time-nuts] Generating a solid PPS from 10Mhz source

Attila, On 01/20/2016 03:21 PM, Attila Kinali wrote: On Wed, 20 Jan 2016 14:13:11 + "Poul-Henning Kamp" wrote: The test results showed a quite more detailed structure with few delays over 100ps and most being between 20ps and 80ps. Interestingly, some were close to

Re: [time-nuts] Generating a solid PPS from 10Mhz source

Hi > On Jan 20, 2016, at 6:28 AM, Attila Kinali wrote: > > On Mon, 18 Jan 2016 14:34:56 -0500 > Bob Camp wrote: > >> The nice thing about a FPGA (or CPLD) is that they come with a cute timing >> analyzer. You can indeed >> answer questions like this with a

Re: [time-nuts] Generating a solid PPS from 10Mhz source

rating a solid PPS from 10Mhz source To: "Discussion of precise time and frequency measurement" <time-nuts@febo.com>, "Attila Kinali" <att...@kinali.ch> Date: Wednesday, January 20, 2016, 8:13 AM In message <20160120122824.39fb655285dd0e68c38

Re: [time-nuts] Generating a solid PPS from 10Mhz source

On Wed, 20 Jan 2016 14:13:11 + "Poul-Henning Kamp" wrote: > >The test results showed a quite more > >detailed structure with few delays over 100ps and most being between > >20ps and 80ps. Interestingly, some were close to 0ps, for which > >we have no explanation good

Re: [time-nuts] Generating a solid PPS from 10Mhz source

In message <20160120122824.39fb655285dd0e68c3884...@kinali.ch>, Attila Kinali w rites: >The test results showed a quite more >detailed structure with few delays over 100ps and most being between >20ps and 80ps. Interestingly, some were close to 0ps, for which >we have no explanation good

Re: [time-nuts] Generating a solid PPS from 10Mhz source

On Mon, 18 Jan 2016 14:34:56 -0500 Bob Camp wrote: > The nice thing about a FPGA (or CPLD) is that they come with a cute timing > analyzer. You can indeed > answer questions like this with a quite high level of confidence. That > *assumes* that you bother to set > up the timing

Re: [time-nuts] Generating a solid PPS from 10Mhz source

The nice thing about a FPGA (or CPLD) is that they come with a cute timing analyzer. You can indeed answer questions like this with a quite high level of confidence. That *assumes* that you bother to set up the timing analyzer :) That true. Its nice looking "Timeng report". I saw the numbers

Re: [time-nuts] Generating a solid PPS from 10Mhz source

On Monday, January 18, 2016 08:45:20 PM you wrote: > > > In message <29659871.S9XTlaFu4r@linux>, Bruce Griffiths writes: > >To detect 100Hz modulation due to photocurrents in the LEDs the 150W > >incandescent bulb had to be placed within a few cm of the LEDs. > > Incandescent bulbs

Re: [time-nuts] Generating a solid PPS from 10Mhz source

On 1/18/16 4:19 PM, Bob Camp wrote: Hi Some time - check out what a “60 Hz” incandescent bulb looks like when hooked to 20 Hz …. flicker flicker flicker … I suspect they optimize the thermal mass of the filament to reduce the flicker at 50/60 Hz. They optimize that to a tiny fraction of a

Re: [time-nuts] Generating a solid PPS from 10Mhz source

On Mon, 18 Jan 2016 20:45:20 +, you wrote: >Incandescent bulbs don't have much "hum" in their light output, >they're basically heating elements and they don't cool down nearly >fast enough. Hook photocell to an audio amp and shine a 60Hz powered lamp on it; you'll be surprised. I don't know

Re: [time-nuts] Generating a solid PPS from 10Mhz source

Hi If you fire up the FPGA and measure it, you will find a sub picosecond jitter on a signal passing through it. If you use the internal PLL or DLL in an FPGA, you might indeed see close to 1x10^-12 ADEV in some cases. In general you should be able to get into the parts in the 10^-13 range

Re: [time-nuts] Generating a solid PPS from 10Mhz source

The clock to output delay of the PIC will be similar or perhaps a little worse. You seem to be confusing delay and jitter. There are zero delay buffers (in the sense that the output transitions are aligned with the clock transitions) but these have excessive jitter due to the internal DLL used

Re: [time-nuts] Generating a solid PPS from 10Mhz source

Hi Some time - check out what a “60 Hz” incandescent bulb looks like when hooked to 20 Hz …. flicker flicker flicker … I suspect they optimize the thermal mass of the filament to reduce the flicker at 50/60 Hz. Bob > On Jan 18, 2016, at 3:45 PM, Poul-Henning Kamp wrote:

Re: [time-nuts] Generating a solid PPS from 10Mhz source

On Sun, 17 Jan 2016 17:32:58 +0100 Gerhard Hoffmann wrote: > I have recently measured the noise of some regulators, LEDs and Zeners > with partly unexpected results. > I'll do a write-up and put it on my web site, but here are 3 pictures > that already tell a lot: Thanks a

Re: [time-nuts] Generating a solid PPS from 10Mhz source

In message <569bc23a.3030...@arcor.de>, Gerhard Hoffmann writes: >LEDs abused as References: This is one of the most stupid ideas ever, because LEDs works both ways. (Back when LED wrist-watches first came out, people soon discovered that they would reset themselves when photographed

Re: [time-nuts] Generating a solid PPS from 10Mhz source

On Wed, 13 Jan 2016 09:22:09 +, Jerome Blaha wrote: > Is there an easy circuit to build that can consistently deliver a 1 PPS > from a 10MHz source with excellent resolution and repeatability? Ulrich B. has made an AVR 1PPS, for those that uses AVR's instead of PIC's AVR PPSDIV 2008-09-06

Re: [time-nuts] Generating a solid PPS from 10Mhz source

Hi, We are drifting from the original problem (dividing 10 MHz to 1 PPS) to general questions such as hardware vs software implementation, obsolescence of parts, program data retention and big program sizes for trivial tasks, all of them also interesting. Well, returning to the main problem

Re: [time-nuts] Generating a solid PPS from 10Mhz source

Hi > On Jan 16, 2016, at 7:40 PM, jimlux wrote: > > On 1/16/16 10:07 AM, Poul-Henning Kamp wrote: >> >> In message <20160116080037.13903406...@ip-64-139-1-69.sjc.megapath.net>, Hal >> Murray writes: >> >>> kb...@n1k.org said: The astonishing part of this

Re: [time-nuts] Generating a solid PPS from 10Mhz source

Am 15.01.2016 um 10:14 schrieb Bruce Griffiths: For lowest jitter the gate power supply noise needs to be very low.Biasing the input at 50% supply helps somewhat but the gate threshold is never exactly 50% and the low pass filtering effect of the coupling capacitor increases the contribution

Re: [time-nuts] Generating a solid PPS from 10Mhz source

Hi Back in the 70’s I was involved in making LCD watches. The whole “photo” issue had not been fully through through. One day our chief marketing guy for the project was driving around in Phoenix AZ. He looks down and notices that his watch is dead. Pops out a spare, puts it on, confirms it it

Re: [time-nuts] Generating a solid PPS from 10Mhz source

You might have come across the Raspberry Pi story : one of the revised versions had a SMPS control chip that was intended to be buried inside a phone, not exposed on an open pcb. https://www.raspberrypi.org/forums/viewtopic.php?t=99042 On Mon, Jan 18, 2016 at 3:11 PM, Bob Camp

Re: [time-nuts] Generating a solid PPS from 10Mhz source

Looking to the complex solutions for the frequency divider (CPLD/MCU), I start to think about skews and propagation delays. Its not obvious from the first glance. But I think such things exists. It could be interesting to compare the numbers. Is it worth to consider some correction to avoid

Re: [time-nuts] Generating a solid PPS from 10Mhz source

se time and frequency measurement" <time-nuts@febo.com> Sent: Monday, January 18, 2016 3:11 PM Subject: Re: [time-nuts] Generating a solid PPS from 10Mhz source Hi Back in the 70’s I was involved in making LCD watches. The whole “photo” issue had not been fully through through.

Re: [time-nuts] Generating a solid PPS from 10Mhz source

Hi, No, the black plastic around ICs isn't black by chance. Einstein got his Nobel price on the photoelectric effect, which is relevant in this case. A few years ago I assisted in modifying a camera for an amateur astronomer. Among the modifications, one was to turn of power for a

Re: [time-nuts] Generating a solid PPS from 10Mhz source

In message <29659871.S9XTlaFu4r@linux>, Bruce Griffiths writes: >To detect 100Hz modulation due to photocurrents in the LEDs the 150W >incandescent bulb had to be placed within a few cm of the LEDs. Incandescent bulbs don't have much "hum" in their light output, they're basically

Re: [time-nuts] Generating a solid PPS from 10Mhz source

Hi The same issue come into random logic. The most common chip logic way to do this is with rippling divide by 10’s. Been there / done that.. The output pulse in that case is delayed by quite a bit. Put a “sync” flip flop on the output and the (obvious) question is — do you know the delay

Re: [time-nuts] Generating a solid PPS from 10Mhz source

On Monday, January 18, 2016 11:45:00 AM Poul-Henning Kamp wrote: > > > In message <569bc23a.3030...@arcor.de>, Gerhard Hoffmann writes: > >LEDs abused as References: > This is one of the most stupid ideas ever, because LEDs works both ways. > > (Back when LED wrist-watches first came

Re: [time-nuts] Generating a solid PPS from 10Mhz source

kb...@n1k.org said: > The astonishing part of this “new world” is that a very complex chip that > is > made in high volume is cheaper than a handful of less popular (but far less > complex) chips. It would be interesting to see the die sizes. Another advantage of the CPU solution is that

Re: [time-nuts] Generating a solid PPS from 10Mhz source

Hi > On Jan 16, 2016, at 3:00 AM, Hal Murray wrote: > > > kb...@n1k.org said: >> The astonishing part of this “new world” is that a very complex chip that is >> made in high volume is cheaper than a handful of less popular (but far less >> complex) chips. > > It

Re: [time-nuts] Generating a solid PPS from 10Mhz source

In message <20160116080037.13903406...@ip-64-139-1-69.sjc.megapath.net>, Hal Murray writes: >kb...@n1k.org said: >> The astonishing part of this “new world” is that a very complex chip that is >> made in high volume is cheaper than a handful of less popular (but far less >> complex)

Re: [time-nuts] Generating a solid PPS from 10Mhz source

On 1/16/16 10:07 AM, Poul-Henning Kamp wrote: In message <20160116080037.13903406...@ip-64-139-1-69.sjc.megapath.net>, Hal Murray writes: kb...@n1k.org said: The astonishing part of this “new world” is that a very complex chip that is made in high volume is cheaper than a handful of

Re: [time-nuts] Generating a solid PPS from 10Mhz source

Thanks to everyone who responded. I guess I'm just showing my age (66). Of course all those considerations of cost etc are all true especially in the world of the professional who has to make the product feasible for the market. I'm a basement tinkerer with a well-stocked junk box for whom

Re: [time-nuts] Generating a solid PPS from 10Mhz source

Am 16.01.2016 um 15:03 schrieb Bob Camp: Unlike the world of lithography, the dicing process has not made a lot of progress. Decades ago a 1mm x 1 mm die was about as small as you could get. From what I can see that has not dropped by more than a factor of two in 40 years (if at all). Yes,

Re: [time-nuts] Generating a solid PPS from 10Mhz source

For lowest jitter the gate power supply noise needs to be very low.Biasing the input at 50% supply helps somewhat but the gate threshold is never exactly 50% and the low pass filtering effect of the coupling capacitor increases the contribution of power supply noise to jitter. A power supply

Re: [time-nuts] Generating a solid PPS from 10Mhz source

On Thu, 14 Jan 2016 09:50:15 -0500 Vlad wrote: > I was thinking to make a frequency divider by using FPGA. Here is my > attempt to implement it using VHDL. > This is frequency divder plus D flip-flop which I was planed to use as > source of 60Hz for my Telechron clock. >

Re: [time-nuts] Generating a solid PPS from 10Mhz source

Am I missing something here? I understand the ease and fun of programming up an AVR as much as anyone but surely this task could be accomplished easily with a chain of fast synchronous TTL or CMOS dividers. A resynchronising FF could also be added at the end to clean up the 1 pps if

Re: [time-nuts] Generating a solid PPS from 10Mhz source

Why use a board full of TTL when an $1 8-pin chip will do it ? On Thu, Jan 14, 2016 at 11:44 PM, Morris Odell wrote: > Am I missing something here? > > I understand the ease and fun of programming up an AVR as much as anyone > but surely this task could be accomplished

Re: [time-nuts] Generating a solid PPS from 10Mhz source

> On Jan 14, 2016, at 3:44 PM, Morris Odell wrote: > > Am I missing something here? > > I understand the ease and fun of programming up an AVR as much as anyone but > surely this task could be accomplished easily with a chain of fast > synchronous TTL or CMOS

Re: [time-nuts] Generating a solid PPS from 10Mhz source

The programmable PIC or AVR or ... chip that will do the job are same or less than a 555 chip, and a lot more flexible. --- Graham On Fri, Jan 15, 2016 at 11:55 AM, Adrian Godwin wrote: > Why use a board full of TTL when an $1 8-pin chip will do it ? > > > On Thu, Jan 14,

Re: [time-nuts] Generating a solid PPS from 10Mhz source

On Friday, January 15, 2016 12:13:47 PM Attila Kinali wrote: > On Thu, 14 Jan 2016 09:50:15 -0500 > > Vlad wrote: > > I was thinking to make a frequency divider by using FPGA. Here is my > > attempt to implement it using VHDL. > > This is frequency divder plus D flip-flop which

Re: [time-nuts] Generating a solid PPS from 10Mhz source

Hi The astonishing part of this “new world” is that a very complex chip that is made in high volume is cheaper than a handful of less popular (but far less complex) chips. To do this with old style logic, you need to divide by 7 decades. If you do three dual decade counters, it’s probably

Re: [time-nuts] Generating a solid PPS from 10Mhz source

Nick wrote: The output from my GPSDO is a square wave, so I didn't condition the input. In the past what I've used for that is a DC blocking cap, followed by a Thevenin termination (100 ohms to ground and Vcc) feeding a 74LVC1G17 Schmitt trigger buffer. I don't know if that's up to Time Nuts

Re: [time-nuts] Generating a solid PPS from 10Mhz source

I'm curious if that code will perform the intended function (down to the clock cycle) when compiled. A check in the simulator would be a good idea while the TIA is busy. If it doesn't give you the performance you are looking for, try programming it in assembly, as was done for the PicDiv. Dan

Re: [time-nuts] Generating a solid PPS from 10Mhz source

Wed, 13 Jan 2016 12:12:39 -0800 > To: nsa...@kfu.com; time-nuts@febo.com > Subject: Re: [time-nuts] Generating a solid PPS from 10Mhz source > From: time-nuts@febo.com > > Just shy of a half dozen folks have asked, so I'll post here as soon as I > finish cleaning it up. I'll put i

Re: [time-nuts] Generating a solid PPS from 10Mhz source

The code is at https://github.com/nsayer/GPS-disciplined-OXCO/blob/master/tiny_divider.c It’s a first cut. The code at the moment will just divide the input clock by 10 million, so you get a 1 PPS 50% duty square wave out. It should run on any ATTinyx5 model - it certainly will fit on at

Re: [time-nuts] Generating a solid PPS from 10Mhz source

e. Can't seem to find anything in the datasheet for the tiny that > explains the maximum frequency on a input pin. > > -=Bryan=- > >> Date: Wed, 13 Jan 2016 12:12:39 -0800 >> To: nsa...@kfu.com; time-nuts@febo.com >> Subject: Re: [time-nuts] Generating a solid PPS from 10Mhz

Re: [time-nuts] Generating a solid PPS from 10Mhz source

I was thinking to make a frequency divider by using FPGA. Here is my attempt to implement it using VHDL. This is frequency divder plus D flip-flop which I was planed to use as source of 60Hz for my Telechron clock. However I never implement it in HW. Instead I was using STM32F4 with its

Re: [time-nuts] Generating a solid PPS from 10Mhz source

On Wed, 13 Jan 2016 14:31:25 +0100, Ole Petter Ronningen wrote: > Sounds like a PICDIV is just about right: > http://www.leapsecond.com/pic/picdiv.htm > Ulrich B made an AVRDIV, for those who use AVR's (bottom of page) http://www.ulrich-bangert.de/html/downloads.html /CFO

Re: [time-nuts] Generating a solid PPS from 10Mhz source

I and others have written divider routines in assembler for the ATtiny25 etc. The version I have is crude but divides by 10, 100, and 1000. I also have a version that divides by 1E4, 1E5, and 1E6. I also have a version that generates 3 pps outputs, one with a 50% duty cycle plus positive

Re: [time-nuts] Generating a solid PPS from 10Mhz source

Following my previous note: today I did create simple test installation using CPLD Xilinx XC2C32A. The project just get input from 50Mhz OSC and divide it to get 1Hz output to send it to two LEDs and defined clk_out pin. As I program it - the LEDs was blinking with 1Hz frequency. Which means

Re: [time-nuts] Generating a solid PPS from 10Mhz source

> On Jan 14, 2016, at 4:20 AM, Daniel Watson wrote: > > I'm curious if that code will perform the intended function (down to the > clock cycle) when compiled. A check in the simulator would be a good idea > while the TIA is busy. I did a test last night (I

Re: [time-nuts] Generating a solid PPS from 10Mhz source

> My test methodology was to feed 10 MHz from one of my GPSDOs into the TIA > reference and the same 10 MHz into the device input. I then had the TIA > perform period measurements with a 10 second gate. The result was 1 second, > ± maybe a dozen or two ps on average, but again, that’s where the

[time-nuts] Generating a solid PPS from 10Mhz source

Hey Guys, Is there an easy circuit to build that can consistently deliver a 1 PPS from a 10MHz source with excellent resolution and repeatability? My first application is to test different 10MHz oscillators without a TIC always attached and then compare the PPS output change over time against

Re: [time-nuts] Generating a solid PPS from 10Mhz source

Tom Van Baak has developed dividers based on simple PIC chips that will produce 1 PPS from several input frequencies. These dividers have remarkably low jitter, down in the couple-of-picosecond range, and are very simple. I've implemented life support circuitry around two versions of Tom's

Re: [time-nuts] Generating a solid PPS from 10Mhz source

Hi! Try TVB's picDiv at http://www.leapsecond.com/pic/picdiv.htm Edésio On Wed, Jan 13, 2016 at 09:22:09AM +, Jerome Blaha wrote: > Hey Guys, > > Is there an easy circuit to build that can consistently deliver a 1 PPS from > a 10MHz source with excellent resolution and repeatability? My

Re: [time-nuts] Generating a solid PPS from 10Mhz source

Sounds like a PICDIV is just about right: http://www.leapsecond.com/pic/picdiv.htm Ole On Wed, Jan 13, 2016 at 10:22 AM, Jerome Blaha wrote: > Hey Guys, > > Is there an easy circuit to build that can consistently deliver a 1 PPS > from a 10MHz source with excellent

Re: [time-nuts] Generating a solid PPS from 10Mhz source

Just shy of a half dozen folks have asked, so I'll post here as soon as I finish cleaning it up. I'll put it on Github when it's ready. I just need a day or two. Sent from my iPhone > On Jan 13, 2016, at 6:43 AM, Nick Sayer via time-nuts > wrote: > > If anyone is

Re: [time-nuts] Generating a solid PPS from 10Mhz source

If anyone is interested in the equivalent functionality using an ATTiny25 (for instance, if you’re already heavily invested in AVR instead of PIC, like I am), ping me. I’ve privately written code to solve almost the same problem and it could easily be adapted into doing the same job. > On Jan