Re: [time-nuts] 5 MHZ PIC PPS Divider?

2008-04-16 Thread SAIDJACK
Hi Bruce, got it, I also like the "pulse stretcher" dual-slope interpolator technique you mention. bye, Said In a message dated 4/16/2008 17:36:44 Pacific Daylight Time, [EMAIL PROTECTED] writes: Another widely used technique is the Wilkinson converter wher the capacitor is charges

Re: [time-nuts] 5 MHZ PIC PPS Divider?

2008-04-16 Thread Bruce Griffiths
Brooke Clarke wrote: > Hi Bruce: > > The A/D used is only 12 bits @ 300 kHz and Linear now has very similar 12 bit > A/D at 600 kHz and 24 bit much slower. Since a s/h is used to capture the > ramp > value the key spec seems to be that the hold time exceeds the conversion > time. > Are ther

Re: [time-nuts] 5 MHZ PIC PPS Divider?

2008-04-16 Thread Brooke Clarke
Hi Bruce: The A/D used is only 12 bits @ 300 kHz and Linear now has very similar 12 bit A/D at 600 kHz and 24 bit much slower. Since a s/h is used to capture the ramp value the key spec seems to be that the hold time exceeds the conversion time. Are there s/h circuits that hold for more than

Re: [time-nuts] 5 MHZ PIC PPS Divider?

2008-04-16 Thread Bruce Griffiths
Bruce Griffiths Correction added: > Said > > Not this particular implementation but have built similar circuits > decades ago. > Tempco isnt an issue. > There's plenty of time to interleave calibration cycles of say 100ns, > 200ns, 300ns, 400ns duration between PPS measurements. > It should e

Re: [time-nuts] 5 MHZ PIC PPS Divider?

2008-04-16 Thread Bruce Griffiths
[EMAIL PROTECTED] wrote: > Hi Bruce, > > did you or anyone every build this LTC application? > > I wonder about the tempco matching of the reference 1N457 diodes > compensating the 2N5771 etc... > > bye, > Said > > Said Not this particular implementation but have built similar circuit

Re: [time-nuts] 5 MHZ PIC PPS Divider?

2008-04-16 Thread SAIDJACK
Hi Bruce, did you or anyone every build this LTC application? I wonder about the tempco matching of the reference 1N457 diodes compensating the 2N5771 etc... bye, Said In a message dated 4/15/2008 21:32:14 Pacific Daylight Time, [EMAIL PROTECTED] writes: For one version of a classic

Re: [time-nuts] Digital TV signals

2008-04-16 Thread SAIDJACK
Hi Ulrich, interesting story. A bit of history from my side: In about 1996 I lived in Stuttgart and we measured the Hs frequencies of the German TV stations at the time. I used a Philips SAA7111 or similar Video decoder's 27,0MHz output (which is line-locked to Hs) to measure the frequency

Re: [time-nuts] 5 MHZ PIC PPS Divider?

2008-04-16 Thread Stanley Reynolds
The two ways I hoped to get around the counter ripple was to measure every other set of PPS with the counter stopped in between. Or two counters running in opposite seconds, one running while the other is stopped. Due to my error not everyone received all the discussion, my email reply puts the

Re: [time-nuts] 5 MHZ PIC PPS Divider?

2008-04-16 Thread Hal Murray
> The ECL part you've selected seems to simplify interfacing with its > synchronous enables. I think you are missing the decimal point. A synchronous enable will have setup/hold times. They will (generally) be less than the cycle time (1 ns). You aren't going to get that level of timing accu

Re: [time-nuts] 5 MHZ PIC PPS Divider?

2008-04-16 Thread Stanley Reynolds
Thank you for your ideas, It will be good for me to go thou the process of improvement one step at a time, I have several steps to try that should keep me busy, I expect to make several prototypes and with some luck try several methods. I do need to bootstrap my self up as I have to develop my

Re: [time-nuts] 5 MHZ PIC PPS Divider?

2008-04-16 Thread Pete
Stanley, Sometimes I get tunnel vision by looking for easy answers in "big box" solutions. Your 1GHz clock solution may be a simpler approach for 1ns resolution & provide a straightforward result. The ECL part you've selected seems to simplify interfacing with its synchronous enables. Perhaps i

Re: [time-nuts] Digital TV signals

2008-04-16 Thread Ulrich Bangert
David, maybe that your TV derived frequency standard IS already obsolete ALTHOUGH you may still receive analogue transmissions! In Germany the ZDF was known to have a rubidium standard in their transmitting central in Mainz that was phase locked to the atomic clock ensemble at the PTB (the German

Re: [time-nuts] Digital TV signals

2008-04-16 Thread Magnus Danielson
From: david brown <[EMAIL PROTECTED]> Subject: [time-nuts] Digital TV signals Date: Wed, 16 Apr 2008 09:25:21 -0700 Message-ID: <[EMAIL PROTECTED]> > From a complete amateur, is there any useful timing info to be gained > from the newer format of digital tv transmission(Australia) to replace >