[time-nuts] Simple GPSDO
denwood at orcon.net.nz
Fri Dec 30 14:59:09 EST 2011
Two thoughts re Simple GPSDOs:
1. For a conventional 1pps approach, see 'A Simple GPS Disciplined
Reference" http://www.qsl.net/zl1bpu/MICRO/SIMPLE/SimpleGPS.htm, by yours
truly. It uses a high performance 10MHz OCXO and gently disciplines it.
Despite not having a Kalmann filter, the holdover is excellent and the Adev
is almost as good as the OCXO allows.
2. The excellent 10kHz design by James G3RUH
http://www.jrmiller.demon.co.uk/projects/ministd/frqstd.htm requires a 10kHz
GPS source, and folk on this group asked where you can get a modern GPS
module with 10kHz output. One suitable answer is any of the u-BLOX modules,
such as the LEA5-P. These have completely programmable pulse outputs in 1us
steps (width and duration). I use an older u-BLOX Antaris 4 development kit
which is Atmel based, and it also has a programmable pulse output.
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