Probe R201 on all 4 WBX boards with an oscilloscope while running. One side of the resistor is ground and the other side is the reference clock. They should all be around the same amplitude, and have the exact same frequency and phase.
Matt On 10/14/2010 09:13 AM, Steven Clark wrote:
Hi all- I have a multi-usrp setup with 2 USRP 1s and 4 WBX daughtercards. I have performed the clock synching described here: http://gnuradio.org/redmine/wiki/1/MultiUsrp I'm doing 4-channel receive, using a power splitter to send the same CW signal into all 4 d'cards, and tuning them all identically. 3 of the 4 channels are nicely phase-locked. The 4th seems a little...off. ClockMasterUSRP (Serial #5821): Side A: "red" channel ClockMasterUSRP (Serial #5821): Side B: "green" channel ClockSlaveUSRP (Serial #2087): Side A: "blue" channel ClockSlaveUSRP (Serial #2087): Side B: "black" channel <--- problem with this guy Please see these 3 images to see the problem: http://picasaweb.google.com/steven.p.clark/MultiUsrpGlitches?feat=directlink You can see the problem in both the frequency domain, and in the time domain. I tried swapping daughtercards around, and the problem is not tied to any one daughtercard, but rather to slave USRP side B. Any idea what could be causing this? Shouldn't the same clock be going to both sides of the USRP? (why does blue look fine, but black does not?) -Steven _______________________________________________ Discuss-gnuradio mailing list [email protected] http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
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