Hello Time-Nuts,
RDR Electronics has a limited supply of FEI FE-405B OCXO oscillators with digital frequency control available. These are very good crystal oscillators that are generally BELOW 1x10E-12 from 1 to 1000 seconds (some approaching a couple of parts in 10E-13). The mediocre ones are in the 1x10E-11 to 1x10E-12 range for 1 to 1000 seconds (still very good). In addition, these units have digital tuning via a serial port that has a resolution of 1.05x10E-14 (no DACs involved, it’s done with a DDS)! These units have a DB-9 connector that is compatible with the FE-5680A and FE-5650A rubidium units (no LOCK or VCXO signal, of course). That’s most of the good news, the bad news is that these are 15MHz oscillators and cannot be changed. There is a 15MHz PLL and crystal filter that are the two largest hurdles. The ovenized oscillator in the unit is at 5MHz, but it is buried deep below all of the rest of the goodies that make these interesting. You can check out lots of FE-405B data on Tom van Baak’s website at http://www.leapsecond.com/pages/fe405/ . There are some slides at the end of all the graphs. You can check out pictures of the unit at: http://rdrelectronics.com/skip/dec/fe4051.jpg http://rdrelectronics.com/skip/dec/fe4052.jpg http://rdrelectronics.com/skip/dec/fe4053.jpg http://rdrelectronics.com/skip/dec/fe4054.jpg http://rdrelectronics.com/skip/dec/fe4055.jpg The jumping around has been solved. It is caused by uP temperature compensation that changes the DDS value based upon the oven heater current. This input to the uP can be grounded which drives the offset to the max value and it stays there. This is absolutely what you would want for a GPSDO so that you don’t have your control loop fighting the temperature compensation. My thinking is that this is what you would want for a reference oscillator as well, but we have left a few units unmodified. After running for a while the aging of these units gets down in the 1x10E-12/day range. In addition, we have set these units so they are reasonably on frequency (parts in 10E-10) with a 00 00 00 00 control value (same commands as the FE-5680 and FE-5650). The range of control values on the FE-405B is F7 33 33 34 to 08 CC CC CC. We have a VERY limited supply that have been characterized by Corby Dawson and his H-maser (thanks) and ADEV plot will be sent with the unit. They fall into three general groups: 1. Temperature compensation disabled, great ADEV (1x10E-12 to 1x10E-13 generally) 2. Temperature compensation disabled, good ADEV (1x10E-11 to 1x10E-12) 3. Temperature compensation intact, great ADEV (1x10E-12 to 1x10E-13 generally) I would like to offer these up to the time-nuts community. Asking $200 for Group 1 and 3 units, $150 for Group 2 units. Postage to the US is $7.10, we will ship international – postage is $26.50. I can send a copy of the ADEV plot for the unit you would receive via email before you decide to purchase if desired. Please send email to [email protected]. Sorry for the long post, and the commercial nature (but it is exclusive to time-nuts at this point). Thanks, Skip Withrow RDR Electronics, Inc. 303-790-1830 _______________________________________________ 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.
