Responses interspersed below. Joe On Sun, 24 May 2015 12:00:01 -0400, [email protected] 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 <[email protected]> > To: Discussion of precise time and frequency measurement > <[email protected]> > Subject: Re: [time-nuts] IRIG-B audio decoder circuits and ICs sought > Message-ID: <[email protected]> > 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 <[email protected]> > To: Discussion of precise time and frequency measurement > <[email protected]> > Subject: [time-nuts] IRIG-B decoder schematic > Message-ID: > <caj_qrvz0e08747ryekqnunggp6x5wtw145n6bcdti6ax6pd...@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 > ****************************************** _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
