Hi That sounds like a close cousin of the Z3805
Bob > On Aug 7, 2015, at 2:53 PM, Arthur Dent <[email protected]> wrote: > > I picked up yet another version of a GPSDO on Ebay the other > day. I thought that I'd mention this because sometimes when > one unit shows up there are a lot more that will be listed > for sale later, like with the many Lucent RFTG units that > are currently being sold on Ebay. > > This one is a Symmetricom CGBA with absolutely no info other > than the photos in the listing. The board is about 9"x13" and > has date codes from 2003. It has a Symmetricom 5Mhz OCXO that > feeds a doubler with L/C filtering and a 10Mhz crystal to > further filter the 10Mhz and give a nice clean sine wave > feeding a 27 ohm termination resistor. Then the signal goes > to 3 EL2257 dual gated opamps That seem to make the signal > look much worse so there may have been more than one design > engineer on this project. ;-) > > I traced out 2 lines for power, each one goes thru its own > fuse to a diode bridge so it doesn't care about polarity. > From the bridge the power goes to several discreet onboard > switchers that give +12, +12 OCXO, -12, +5, and +3.3VDC. I > found that the minimum voltage to make the board operate was > 22-28VDC so I'm running it on 36VDC. The current draw is 0.5A > cold to 0.25A with the OXCO warmed up. > > The GPS is made by Furumo and has what looks like an HP part > number 0960-1060(HP31) and has +5VDC for an active antenna on > the antenna connector. There are unused pads on the main board > for SMA size connectors that are marked 10M, PP2S, 4.096M, 100Hz, > 30.72M, 40.96S, and 8K. Not all of these are active and the > 3 dual opamps are not 'on' either so some of the pins in the > connectors on the back of the assembly may do some controlling > of signals or these may be options not implemented on this board. > > When powered up it goes through a light flashing sequence then > the GPS LED goes flashing green when it sees the satellites, then > solid green when it locks, and the ACT LED turns from flashing red > to flashing green. Using my modified Tbolt to test the unit shows > it stays within +/-200PPT for about the first 2 hours then settles > down. > > There is an RJ-45 connector on the front plus there is a 15 pin > 'D' connector behind the panel that may have been for some > testing purpose because it can't be accessed from the front. > At this time I'm just happy to see how well it works and later > I'll see if I can communicate with it somehow. > > -Arthur > > http://i906.photobucket.com/albums/ac262/rjb1998/CGBA_zpsd4rricto.jpg > _______________________________________________ > 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. _______________________________________________ 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.
