[time-nuts] IRIG-B audio decoder circuits and ICs sought

[Azelio Boriani]

The schematic seems to have 4 pages (only page 2 is in the PDF) and
the description indicates that ICs Z19, Z14 and Z10 recover the IRIG
code but the relative schematic page is missing...

On Sun, May 24, 2015 at 9:55 PM, Joseph Gwinn <joegwinn at comcast.net> wrote:
> Responses interspersed below.  Joe
>
> On Sun, 24 May 2015 12:00:01 -0400, time-nuts-request at febo.com wrote:
>>
>> Today's Topics:
>>
>>    9. Re: IRIG-B audio decoder circuits and ICs sought (Esa Heikkinen)
>>   13. IRIG-B decoder schematic (Tim Shoppa)
>>
>>
>> ----------------------------------------------------------------------
>>
>>
>> ------------------------------
>>
>> Message: 9
>> Date: Sun, 24 May 2015 10:33:47 +0300
>> From: Esa Heikkinen <tn1ajb at nic.fi>
>> To: Discussion of precise time and frequency measurement
>>       <time-nuts at febo.com>
>> Subject: Re: [time-nuts] IRIG-B audio decoder circuits and ICs sought
>> Message-ID: <55617EDB.5070706 at nic.fi>
>> Content-Type: text/plain; charset=UTF-8; format=flowed
>>
>> Joseph Gwinn kirjoitti:
>>
>>> When I last used IRIG-B005, the vendor (Symmetricom?) said it was good
>>> for a few meters only on shielded twisted pair. I recall that the
>>> handling of shield grounds was strange.   This was OK, because the
>>> signal was confined to one cabinet, and it worked just fine.
>>> But there was no mention that the B005 followed RS422 or RS485 or
>>> anything else.  Nor does IRIG 200-04 say this, so I suspect that each
>>> company solves it differently.
>>
>> Yes, there seems to be many implementations.
>> Quote from Technical Note TN-102 from Cyber Sciences:
>> <http://www.cyber-sciences.com/documents/TN-102_IRIG-B.pdf>
>>
>> The IRIG 200-04 standard does not define specific signal levels for IRIG-B.
>> Typical techniques for transmission of unmodulated IRIG-B include:
>> - TTL-level signal over coaxial cable or shielded twisted-pair cable
>> - Multi-point distribution using 24 Vdc for signal and control power
>> - RS-485 differential signal over shielded twisted-pair cable
>> - RS-232 signal over shielded cable (short distances only)
>> - Optical fiber
>> Typical techniques for transmission of modulated IRIG-B include:
>> - Coaxial cable, terminated in 50 ohms or higher.
>> - Shielded twisted-pair cable
>>
>> So your main concern with unmodulated version is compatibility between
>> different vendors.
>
> Yes, now and in the future as things fail and are replaced.
>
>
>>>> Yes, planning to buy at least one spare unit when their prices will drop
>>>> on Ebay... :)
>>> The problem is that they don't handle GPS week field overflow gracefuly.
>>
>> Yes. Internal GPS of TS2100 cannot be used anymore, it failed alrady in
>> February. Used external PPS since then. Since having external PPS is
>> major problem for most of the TS2100 users I hope that the price of
>> these units will drop soon on Ebay.
>>
>> I'm interested to buy especially rubidium version of the TS2100, if
>> someone has working one having only the GPS problem...
>
> Are you trying to synchronize a Rb unit via IRIG-B12x?  Tried that
> once.  It doesn't work - the IRIG-B12x signal can wiggle faster that
> the Rb can follow, so the Rb never syncs, or the sync is ratty and
> fragile.  IRIG-B005 can work though.  That was the solution.
>
>
>
>>
>> ------------------------------
>
>>
>>
>> ------------------------------
>>
>> Message: 13
>> Date: Sun, 24 May 2015 07:05:14 -0400
>> From: Tim Shoppa <tshoppa at gmail.com>
>> To: Discussion of precise time and frequency measurement
>>       <time-nuts at febo.com>
>> Subject: [time-nuts] IRIG-B decoder schematic
>> Message-ID:
>>       <CAJ_qRvZ0E08747RYeKQNuNGgP6X5wTW145n6bCDti6AX6PdPag at mail.gmail.com>
>> Content-Type: text/plain; charset=UTF-8
>>
>> Truetime 820 was made in the 80's and 90's and we have many at my day job
>> fed with 1kHz AM modulated IRIG-B120.
>>
>> Schematic at http://www.trailing-edge.com/IRIG-B-DECODER.pdf
>>
>> Useful if you also have the theory of operation at
>> http://www.arsitec.com.br/arquivos/produtos/man-820-210.pdf
>>
>> Tim N3QE
>
> Got them; thanks.  I'll sturdy them.
>
>
>
>> ------------------------------
>>
>> End of time-nuts Digest, Vol 130, Issue 35
>> ******************************************
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