[time-nuts] IRIG B

Bob Camp lists at rtty.us
Tue May 25 21:12:47 UTC 2010


Hi

I *think* Clive is looking for a chip set to put on a pc board in a product.

Bob

-----Original Message-----
From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
Behalf Of Don Latham
Sent: Tuesday, May 25, 2010 1:20 PM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] IRIG B

16 bit audio interfaces with USB adapters (cheap sound cards) are
available made in the old country for less than ten inflated rasbuckniks
on epray...
Don

Bob Camp
> Hi
>
> Audio codecs (especially monophonic ones) are pretty cheap these days.
> Depending on volume they can get to the sub $1 range. Even in small
> quantity
> they are below $4. That makes them a pretty tempting "front end" for a
> send
> / receive box.
>
> Bob
>
> -----Original Message-----
> From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
> Behalf Of Dean Weiten
> Sent: Tuesday, May 25, 2010 9:05 AM
> To: cgreen at quartzlock.com
> Cc: time-nuts at febo.com
> Subject: Re: [time-nuts] IRIG B
>
> Date: Tue, 25 May 2010 09:08:18 +0100
> From: "Clive Green" <cgreen at quartzlock.com>
> Subject: [time-nuts] IRIG B
> To: <time-nuts at febo.com>
> Message-ID: <000d01cafbe1$6f6788b0$4e369a10$@com>
> Content-Type: text/plain;	charset="iso-8859-2"
>
> Can anyone help with a modern IRIG B chipset manufacturer
>
> Many thanks
>
> Clive Green
>
> ----------------------
>
> Hi Clive and the group.
>
> I can't give you a lead on an ready-made chipset, but I've implemented an
> IRIG-B decoder in a 68HC11 and in an 68HCS12.  I found the difficult part
> to
> be the analog section, as it can introduce significant uncertainties in
> the
> timing stream, especially in a modulated signal.  We got ours down to
> around
> 10 uSec which we considered quite good.  Of course the 5 volt logic levels
> of the unmodulated signal makes it easier to get better accuracy.
>
> The IRIG-B decoder work I did was implemented on power systems relays &
> disturbance recorders several years ago, then I left the company and in
> the
> meantime, they changed over to an FPGA implementation and skipped the
> processor altogether.  Now I'm back with that same company (although
> ownership has changed), but I haven't yet had a chat with the new FPGA
> designer to find out how he did it :-)
>
> I've also tweaked and "upgraded" (well in my opinion) the TG program of
> the
> NTP package, which generates WWV(H) and IRIG-B audio signals in *NIX
> operating systems.  It was targeted for the Sun Sparc and I moved it to
> OSS
> audio which was what I was using on X86 GNU/LINUX at the time.  I think I
> submitted it for inclusion in the NTP package but I don't think it ever
> got
> in there; I used to claim that it was rejected, but then again it's also
> possible that I didn't submit it correctly.  I can give this to you if you
> would like.
>
> If you would advise on your application and parametric requirements,
> perhaps
> I (or someone else on the mailing list) could make further suggestion or
> help directly.
>
> --
>
> Dean Weiten
>
>
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-- 
"Neither the voice of authority nor the weight of reason and argument are
as significant as experiment, for thence comes quiet to the mind."
R. Bacon


Dr. Don Latham AJ7LL
Six Mile Systems LLP
17850 Six Mile Road
POB 134
Huson, MT, 59846
VOX 406-626-4304
www.lightningforensics.com
www.sixmilesystems.com


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