Re: [time-nuts] Shera revisted

On Fri, 12 Aug 2016 13:56:40 +0200 Paul Boven wrote: > I'd want to use the programmable logic to build a (mostly) digital > interpolation, either something along the lines of the 5370, or digital > interpolation of the clock using DCM's like I did on a Spartan-3 years >

Re: [time-nuts] Shera revisted

On Friday, August 12, 2016 12:21:55 PM David wrote: > On Fri, 12 Aug 2016 13:56:40 +0200, you wrote: > >Hi everyone, > > > >On 2016-08-11 21:06:12, Attila Kinali wrote: > >> Hoi Bert, > >> > >> I'm asking, because if you go the way of using a CPLD anyways, you could > >> throw in another $2 for

Re: [time-nuts] Shera revisted

On Fri, 12 Aug 2016 13:56:40 +0200, you wrote: >Hi everyone, > >On 2016-08-11 21:06:12, Attila Kinali wrote: >> Hoi Bert, > >> I'm asking, because if you go the way of using a CPLD anyways, you could >> throw in another $2 for an opamp to build a time-to-amplitude converter >> (à la PICTIC II)

Re: [time-nuts] Shera revisted

Hi It might be easier to get into this if we put numbers on some of this. Are we after a 16X increase from 10 ps (10 ps -> 0.6 fs) or from 10 ns (10 ns -> 600 ps). There’s a lot of range there :) Testing things like temperature dependance and noise / spurs can be challenging in some of

Re: [time-nuts] Shera revisted

Hi everyone, On 2016-08-11 21:06:12, Attila Kinali wrote: Hoi Bert, I'm asking, because if you go the way of using a CPLD anyways, you could throw in another $2 for an opamp to build a time-to-amplitude converter (à la PICTIC II) and boost the resolutiong from 40ns to <100ps. As you would be

Re: [time-nuts] Shera revisted

Hoi Bert, On Wed, 10 Aug 2016 09:33:30 -0400 Bert Kehren via time-nuts wrote: > I get repeated requests for info on Shera mainly for Rb applications. Shera > has a successful history controlling Rb's. Two things are a problem. The > AD 1861 is not only unavailable but

Re: [time-nuts] Shera revisted

There are also some nice cypresses semiconductor parts that are similar and have a really nice dev environment. Basically a core surrounded by programmable logic. Code in C ore close to it. > On Aug 11, 2016, at 07:06, Bob Camp wrote: > > Hi > > To your earlier point,

Re: [time-nuts] Shera revisted

On 8/10/16 8:18 PM, Chris Albertson wrote: Thanks for pointing out the Zynq. Wow you get a dual core ARM and an FPGA all in one package. It seems overkill for a GPSDO but not the type you are making as you can transferring the time out of the GPSDO using PTP. The Zyng looks to the the

Re: [time-nuts] Shera revisted

Hi To your earlier point, there are a number of fairly low cost boards with Zynq’s on them. They aren’t into the $5 range, but they are not that much more than one of the Beagle boards. Bob > On Aug 10, 2016, at 11:18 PM, Chris Albertson > wrote: > > Thanks

Re: [time-nuts] Shera revisted

You are so right, Chris. The Zynq is absolutely an overkill for an ordinary GPSDO. What I think is attractive with the Zynq are the possibilities to experiment with different implementations of counters and gates without soldering and that you can get pretty fast counters well integrated with

Re: [time-nuts] Shera revisted

The Red Pitaya uses a Zynq, and there's an (unofficial) SDR application available to experiment with. Cheers Michael On Thursday, 11 August 2016, Chris Albertson wrote: > Thanks for pointing out the Zynq. Wow you get a dual core ARM and an > FPGA all in one package.

Re: [time-nuts] Shera revisted

Thanks for pointing out the Zynq. Wow you get a dual core ARM and an FPGA all in one package. It seems overkill for a GPSDO but not the type you are making as you can transferring the time out of the GPSDO using PTP. The Zyng looks to the the perfect platform for low-cost SDR. On Wed, Aug 10,

Re: [time-nuts] Shera revisted

Dear time-nuts, My name is Joakim Langlet (SM0OET) and I just recently joined this list. As Brooks Shera was mentioned, I remembered that I was referenced in the footnotes of the original article in the QST - July 1998. It feels almost historical now. Brooks bought a few OCXOs from me. I am

Re: [time-nuts] Shera revisted

On Wed, Aug 10, 2016 at 6:33 AM, Bert Kehren via time-nuts wrote: ..The LTC 1655 makes a perfect replacement ,16 bits is more than > enough and covers range and resolution. What is needed is someone proficient > with PIC assembly programming. Even if you solve this

[time-nuts] Shera revisted

I get repeated requests for info on Shera mainly for Rb applications. Shera has a successful history controlling Rb's. Two things are a problem. The AD 1861 is not only unavailable but also never intended for precise DAC applications. The LTC 1655 makes a perfect replacement ,16 bits is