Re: [time-nuts] Question about AD9832 "I out Full Scale" (what does it mean?)

With no internal PLL to generate a higher internal frequency than the 25MHz MCLK, that 1MHz waveform looks a bit too smooth for an unfiltered 1MHz output. Bruce On Friday, 18 November 2016 5:12 PM, Richard (Rick) Karlquist wrote: Trying to figure out what "Iout

[time-nuts] Question about AD9832 "I out Full Scale" (what does it mean?)

Trying to figure out what "Iout Full Scale" means on the AD9832. Some time nuts may have used this one. On page 7 of this doc: http://www.analog.com/media/en/technical-documentation/user-guides/UG-313.pdf It shows the AD9832 output as 572 mV peak to peak across 300 ohms. This works out to 1.9

Re: [time-nuts] precision timing pulse

Am 18.11.2016 um 02:18 schrieb Bob Camp: If you head of into ARM land (or even FPGA’s) there is a bit of a gotcha. If you want to run a 10 MHz input and a PPS output, you need a counter with at least 24 bits. The peripherals on ARM chips are all over the place. Some have very fancy timers, but

Re: [time-nuts] precision timing pulse

Hi If you head of into ARM land (or even FPGA’s) there is a bit of a gotcha. If you want to run a 10 MHz input and a PPS output, you need a counter with at least 24 bits. The peripherals on ARM chips are all over the place. Some have very fancy timers, but only go to 16 bits. Some have 32 bit

Re: [time-nuts] precision timing pulse

Tom describes the PIC as a 'poor man's FPGA'. And I'm aware of how they're programmed - I agree they're a good choice for this sort of device. However, even poor men can use FPGAs now. I'm following with interest the open-source toolchain available for the Lattice ice40,

Re: [time-nuts] precision timing pulse

Sorry, meant the ARM pin on the picdiv not the ARM MCU's -=Bryan=- From: time-nuts on behalf of Bob Camp Sent: November 17, 2016 2:07 PM To: Discussion of precise time and frequency measurement Subject: Re:

Re: [time-nuts] precision timing pulse

On Wed, Nov 16, 2016 at 8:52 PM, jimlux wrote: > On 11/16/16 7:17 PM, Hal Murray wrote: > >> >> t...@leapsecond.com said: >> >>> Arduino probably uses compiled code, external libraries, and interrupts >>> so >>> that also is a no-no for precise time. >>> >> >> There are two

Re: [time-nuts] precision timing pulse

For counting and timing the ARM has hardware counbter/timmer that is made with logic gates so you don't need software or to disable interrupts. Most modern uP has loads and loads of peripheral hardware built-in. With the ARM there is a lot more of these peripheral devices than there are pins on

Re: [time-nuts] precision timing pulse

If the OP would contact me I would be happy to make a new PIC divider for his specific purpose. I do this all the time. It usually only takes a few minutes. On the PIC 12F675, pin5 / GP2 is Schmitt trigger. See page 8 of 41190F-PIC-12F629-675.pdf But for push-button-start sorts of things input

Re: [time-nuts] precision timing pulse

Hi There are a number of us on the list who code on ARM MCU’s. Doing the same thing on one of them is *not* a trivial undertaking. Making sure that it does what it should simply is not worth the effort. The PIC 12 is a low cost solution and has been extensively tested to show that it does what

Re: [time-nuts] precision timing pulse

Tom: As you were gracious to release the source code for these excellent little dividers, I would suspect someone who is somewhat fluent in assembly could just modify so it counts a specific number of pulses and then toggles a output off. The ARM could be used to restart etc. Although I think

Re: [time-nuts] Thermal impact on OCXO

Hi The advent of welded packages for OCXO’s started to make the “blowtorch” approach obsolete back in the 1990’s. The real problem, even backing in the 1980’s is that there is no market for rejects. The only high value part in an OCXO is the crystal. It is the cause of the performance reject,

Re: [time-nuts] precision timing pulse

On Wed, 16 Nov 2016 11:14:59 -0800, you wrote: >albertson.ch...@gmail.com said: >> I'm wondering why everyone seems to be assuming a PIC is the right processor > >If you want cycle-accurate timing, one approach is to count cycles. If you >have an assembly level background, the PIC is as good as

Re: [time-nuts] Thermal impact on OCXO

Hi Bob, said:  "Most (> 99%) OCXO’s are made to custom specs for large OEM’s. The sort consists of “ship these” and “send these to the crusher”.  Needless to say, the emphasis is on a process that throws out as few as possible. " We've seen a serious improvement in manufacturing yields at close

Re: [time-nuts] Thermal impact on OCXO

Hi > On Nov 17, 2016, at 10:34 AM, Scott Stobbe wrote: > > I couldn't agree more, that, once you add a correlated disturbance or > 1/f^a power law noise, things get even messier. Gaussian is just the > easiest to toss in. > > I once herd a story from once upon a time

Re: [time-nuts] Thermal impact on OCXO

On Thu, 17 Nov 2016 10:34:06 -0500 Scott Stobbe wrote: > I couldn't agree more, that, once you add a correlated disturbance or > 1/f^a power law noise, things get even messier. Gaussian is just the > easiest to toss in. Side note: 1/f^a noise is (usually) Gaussian.

Re: [time-nuts] A (slightly) different apu2 question

> > > NTP does not require softstamps. NTP can be (and I believe it has been in > a product) modified to use "PTP" hardware (hardstamps) and reasonably > current releases can run with "drivestamps" (sampled in the NIC driver) > between cooperating endpoints. Of course it does not *require*

Re: [time-nuts] A (slightly) different apu2 question

On Thu, Nov 17, 2016 at 9:42 AM, Wojciech Owczarek wrote: > ... waste what's > left by then retransmitting it via NTP with software timestamping. I am not > saying that there is anything wrong with NTP, just that software packet > transmission and receipt timestamps ruin

Re: [time-nuts] Thermal impact on OCXO

I couldn't agree more, that, once you add a correlated disturbance or 1/f^a power law noise, things get even messier. Gaussian is just the easiest to toss in. I once herd a story from once upon a time that, if you bought a 10% resistor, what you ended up with is something like this in the figure

Re: [time-nuts] Thermal impact on OCXO

It sounds like you knew what I meant by linearization, but I really should have wrote linearize in parameters. Of course functions like F = Ax^2 + Bx + C F = Asin(omega t) + Bcos(omega t) fit extremely well with ordinary least squares. Well there is no free lunch, nlsq has its own challenges,

Re: [time-nuts] A (slightly) different apu2 question

...do excuse the slightly off-topic 5(insert your preferred sub-currency here). I think many people put a significant effort into getting a precise pulse into a board like the APU2, losing a lot of precision and accuracy by getting it into the O/S software clock, and then perfectly waste what's

Re: [time-nuts] precision timing pulse

On 11/17/16 4:45 AM, Bob Camp wrote: Hi On Nov 16, 2016, at 11:52 PM, jimlux wrote: On 11/16/16 7:17 PM, Hal Murray wrote: t...@leapsecond.com said: Arduino probably uses compiled code, external libraries, and interrupts so that also is a no-no for precise time.

Re: [time-nuts] Thermal impact on OCXO

On Tue, 15 Nov 2016 23:58:31 -0500 Scott Stobbe wrote: > Do you recall if you fitted with true ordinary least squares, or fit with a > recursive/iterative approach in a least squares sense. If the aging curve > is linearizable, it isn't jumping out at me. Least square

Re: [time-nuts] precision timing pulse

On Wed, 16 Nov 2016 20:47:52 -0800 jimlux wrote: > The BeagleBoard Black is a bigger, more capable example.. You can > actually run a *nix on it, but has device drivers and such for lots of > GPIO and timers. And additionally has two PRU units, which are basically uC's

Re: [time-nuts] A (slightly) different apu2 question

On Wed, 16 Nov 2016 15:24:06 -0800 Jay Grizzard wrote: > On the apu2, this crystal is easily accessible (at least as easy as > anything SMD is). Can anyone think of a reason that it wouldn't be > feasible to replace this crystal with an external reference, à la

Re: [time-nuts] precision timing pulse

Hi > On Nov 16, 2016, at 11:52 PM, jimlux wrote: > > On 11/16/16 7:17 PM, Hal Murray wrote: >> >> t...@leapsecond.com said: >>> Arduino probably uses compiled code, external libraries, and interrupts so >>> that also is a no-no for precise time. >> >> There are two

Re: [time-nuts] A (slightly) different apu2 question

Sorry if this is a dup. I had accidentally left the « SPAM » prefix on my first reply. > Le 17 nov. 2016 à 00:24, Jay Grizzard a écrit : > > So there's been a lot of discussion going around on how to do GPS foo on > pcengines.ch's apu2 hardware, but there's one