In a message dated 12/12/2007 14:11:50 Pacific Standard Time, [EMAIL PROTECTED] writes:
>Now I am not sure which of any of the above points are necessary or >important but I would be grateful for the thoughts of others. >Regards Rex VK7MO Hi Rex, that's a lot of great information! Since you are not too concerned about overall frequency accuracy (I assume 1 to 5E-09 would be acceptable) you may not need to or want to lock to GPS at all. With a typical OCXO retrace of 5E-09 you would have a (fairly stable) frequency offset of 235Hz or so at 47GHz. As you mentioned your requirement to be ~2Hz deviation at 47GHz this calculates to about 4.3E-011 stability over 46 seconds. GPS itself cannot deliver that, but a good OCXO flywheel will do that. Any GPSDO with ADEV better than 5E-011 should be sufficient locked to GPS or not, but you may have to keep the oven on at all times as you said. Tom measured the Fury's ADEV (double oven) to achieve this performance above measurement intervals of 0.01 seconds already so that should work really well, and in this short time frame (46 seconds) it's pretty much all up to the OCXO (aging and tempco correction by the processor should not be a factor at 46s intervals either). Thus a good MTI double oven OCXO should do the trick for you and GPS locking is not really needed, except maybe for getting initial frequency accuracy. The advantage of this is that a typical MTI Eurocan double-oven OCXO consumes only about 1.7W and can thus be safely and easily powered by a car battery. bye, Said **************************************See AOL's top rated recipes (http://food.aol.com/top-rated-recipes?NCID=aoltop00030000000004) _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
