EEVblog Electronics Community Forum
Electronics => Projects, Designs, and Technical Stuff => Topic started by: cncjerry on February 17, 2024, 11:47:40 pm
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Hi,
Anyone have experience with the subject unit?
I bought a Symmetricom X72 Microchip 560-5203 10Mhz GPSDO Card. I wanted the X72 that is in it. I have experience with them having two. They are decent little Rubidium units that usually sell for around $300 and this was 1/3 that price. I had planned to pull the X72 out but then I started looking at the pictures and thinking, hey, if I can get power to it, the board has several SMA coaxial connectors, maybe I can get it running as a unit.
You can discipline the X72 multiple ways so I'm not worried if I can't run the board. For instance, if you feed an X72 1pps, Lady Heather V6 will calculate the tuning word from a serial link and update the X72. You can then write the new tuning word to the X72 if the power fails. You can also discipline the X72 using EFC from a PLL/phase detector. I also disciplined it by setting the tuning word over a serial link instead of the EFC pin. Lady Heather will do this or an arduino, etc.
The X72 has a secondary oscillator. You can send it an integer divider and output another sine wave. Depending on the crystal (30Mhz and 60Mhz are known) you can send it a '6' for instance and get 5Mhz or 10Mhz, 6 or 12Mhz for a '5', etc., respectively.
The X72 runs ok off a wall wart if you insert an LT3045 in series to clean-up the power. If you need low phase noise, you can again phase lock the X72 sine output to a better oscillator as a clean-up. Unlike other Rb units I have, this one takes like from 10v to 15v or higher and doesn't need a secondary 5v for logic. My other Rb units need 24v for the lamp and 5V for the logic, but you can turn the 5v off when not needed.
If you have a TrueTime, let me know. I've been searching around for schematics, etc.
Jerry