Author Topic: Open Source 10Mhz Isolated Distribution Board, TruePosition GPSDO and Enclosure  (Read 4910 times)

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Offline RoadRunnerTopic starter

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After reading a post on forum. I got few TruePosition GPSDO board for my self. As i am also working on my own GPSDO project. I decided to put these in an enclosure and a 4 or 6 channel Isolated  distribution board.  all of the source are available in my github account. you are free to use.

https://www.circuitvalley.com/2018/07/diy-isolated-10mhz-distribution-amp-gpsdo-rubidium-tcxo-reference.html

https://www.circuitvalley.com/2018/07/gpsdo-10mhz-standard-reference-clock-distribution-trueposition-gps-tcxo-ocxo.html



« Last Edit: July 18, 2018, 06:31:41 pm by RoadRunner »
 
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Offline awallin

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Thanks for posting this! good work.

I've listed links to a few different distribution amplifier projects on this ohwr-page:
https://www.ohwr.org/projects/pda-8ch-fda-8ch/wiki/similar-projects
I just added the circuitvalley and github links.

do you have a measurement of the residual phase noise of the amplifier?
 

Online Gerhard_dk4xp

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Hey, you have forgotten mine :-)

http://www.hoffmann-hochfrequenz.de/downloads/DoubDist.pdf   >
The phase noise plot includes the GPS receiver/ MTI-260 and the doubler.

upto 200 MHz:
< http://www.hoffmann-hochfrequenz.de/downloads/iso_amp.pdf   >

and a 17 dBm version in the photo, which has twice the transistors
for the larger dissipation required. They don't have a future because
they use shiploads of BFG31, and there are no RF PNPs anymore.
(OK, I still have a reel that's nearly full.)
The latter two amplifiers are effectively incarnations of these publications:

https://tf.nist.gov/general/pdf/1200.pdf   >
https://tf.nist.gov/general/pdf/498.pdf     >

Cheers,
Gerhard
 

Offline awallin

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Hey, you have forgotten mine :-)

http://www.hoffmann-hochfrequenz.de/downloads/DoubDist.pdf   >
The phase noise plot includes the GPS receiver/ MTI-260 and the doubler.

Thanks! added link to the ohwr page  :-+

It's a shame if the transistors aren't available anymore - for as-low-as-possible phase noise I guess one can achieve better performance with a discrete design compared to op-amps.
I've looked inside some commercial boxes where they pair two LMH6702s together to get a 3dB reduction.. (a bit like the ADA4898 LNA idea!)
 


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