Re: [time-nuts] ACAM GP22 Chip

N'abend On Wed, 25 Nov 2015 14:19:37 - "Thomas Allgeier" wrote: > You guessed my origin right from my name. > > It is not that I don't trust ACAM (we are one of their customers) but from > the source I am measuring I get a lot of what you guys probably call jitter.

Re: [time-nuts] ACAM GP22 Chip

On Wed, 25 Nov 2015 14:19:37 - "Thomas Allgeier" wrote: > It is not that I don't trust ACAM (we are one of their customers) but from > the source I am measuring I get a lot of what you guys probably call jitter. > So I want to be sure the jitter comes from the

Re: [time-nuts] ACAM GP22 Chip

Hi To me the easy way to do the buffers: !) Grab some buffers or inverters in a reasonable package. The 74ACT14 in a PDIP-14 package seems to sell for about 50 cents. 2) Power the gate off of 5V, it’s TTL input so it will trigger at 1.4 V 3) Hook the inputs of 5 inverters to the output of

Re: [time-nuts] ACAM GP22 Chip

I don't want to muddy the water too much, but I'd second going all-digital, along the lines of what Bob L. recommended earlier. It seems like you just need to make some specific delay times, so various logic counting or shifting circuits should be just fine - and well-defined and understood.

Re: [time-nuts] ACAM GP22 Chip

On Wed, 25 Nov 2015 12:35:44 -0800 Hal Murray wrote: > If you poke around on the web you can probably find a graph of frequency vs > temperature, maybe even for that particular vendor/model of crystal if you > can read the label. Beware: the graph for a 32 KHz crystal

Re: [time-nuts] ACAM GP22 Chip

>> In order to evaluate the chip I was planning to replicate John A’s >> experiment with the coaxial delay line from the HP5370b > For those wondering: "John A" is John Ackermann and the experiment > in question is documented at http://www.febo.com/pages/hp5370b/ Maybe I misunderstand, but I

Re: [time-nuts] ACAM GP22 Chip

>I wouldn't expect the noise to >be in the ns range, but i wouldn't surprised if it was a few 10ps. >I have never done any measurements though, and I don't think i've >ever seen any jitter measurements for 32kHz oscillators, so take >this value as rough guestimate. On the GP21 board I used it

Re: [time-nuts] ACAM GP22 Chip

Hi Thomas, Another option for generating a range of delays would be to use a stable oscillator like an ovenised one. This is actually similar to what the GP22 does for measuring on mode2. If you gate the output of the oscillator you can get a start and stops at 1us or 70us or whatever. It's

Re: [time-nuts] ACAM GP22 Chip

FWIW I think the two books T versus AofE complement one another quite well Regards, David Partridge -Original Message- From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Attila Kinali Sent: 25 November 2015 10:25 To: Discussion of precise time and frequency measurement

Re: [time-nuts] ACAM GP22 Chip

Hello Hal, The book has been sourced and is on its way to me - a good pointer, thanks. With it and the comments I have had from you guys I expect I will get pretty much what I want, given a little time which thankfully I have. I will report back any outcome that looks plausible /

Re: [time-nuts] ACAM GP22 Chip

Hello Bob, That kind of approach is what I had in mind and as others have commented if done carefully (which for me means a bit at a time) should get me there. The buffers may present a bit of a challenge to a mechanical engineer (unless they are the kind that can be salvaged from railway

Re: [time-nuts] ACAM GP22 Chip

th.allge...@gmail.com said: > Absolute accuracy is not the problem here, unless the 32768 Hz clock on the > eval board actually drifts. ... It will drift with temperature. Not much, but this is time-nuts. Coax or R-C delay lines will probably drift more. If you poke around on the web you can

[time-nuts] Nortel GPSDO

All: Several years ago, I purchased (from the ePlace) one of these units that many of you commented favorably on. While it worked and communicated properly with Lady Heather, I never got it to completely lock in -- some form of periodic noise on the oscillator voltage. It has been

Re: [time-nuts] ACAM GP22 Chip

Moin Attila, You guessed my origin right from my name. It is not that I don't trust ACAM (we are one of their customers) but from the source I am measuring I get a lot of what you guys probably call jitter. So I want to be sure the jitter comes from the oscillator I am measuring and not from

Re: [time-nuts] ACAM GP22 Chip

Dear Paul, Thanks for the reply and thanks to all other contributors. Seems I have subscribed to the right list! As it happens this is a sideline project. So I have the luxury to ask for advice and even consult books before advancing with care. I will probably try and go down the coax

Re: [time-nuts] ACAM GP22 Chip

Hello Bob, Thanks for the suggestions - these sound a bit beyond my current level of skills and kit. But I do have people to call on in the office who may be able to rig something like that up for me should the coax route fail. Best regards, Thomas. - Original Message - From:

Re: [time-nuts] ACAM GP22 Chip

On Tue, 24 Nov 2015 11:44:04 -0800 Hal Murray wrote: > th.allge...@gmail.com said: > > I should say from the start that I am new to time and frequency measurements > > and not even an electronics engineer – but then I have been exposed to > > high-precision electronics