> The current implementation used in WR was developed by Tomasz > Wlostowski in the frame of his MSc thesis, following the ideas of > Pablo Alvarez which Bruce pointed to earlier. As you can see in > Tomasz's dissertation [1], there was not a lot of investigation on > optimal strategies for DDTMD noise. The precision at the time was > deemed more than adequate. It is very timely that you bring up this > subject now, because I hope to start looking at ways to optimize phase > noise in WR in the coming months, and noise coming from the DDMTD > phase detector is definitely something I want to look at. I will be > very interested in your ideas and findings regarding optimal > strategies for the de-glitcher. > >
Hi Simon and Javier, I arrive late to this discussion but I would like to add my grain of salt. As Javier says there was not a detailed optimization of the DDMTD architecture as jitter was already limited by all the surrounding electronics. I would like to add that much of the noise rejection is due to the implementation of a median estimator for the incoming edge position respect to the "slightly-offset" oscillator. It is easy and fun to proof that this median estimator can be implemented with a counter counting the number of sampled zeros and a simple state machine state machine that places counter start in a safe zone. In fact, when you think it out, the most curious thing is that this algorithm is nothing more than a sort of generalization of the bang-bang architecture to measure phase offsets. Cheers, Pablo _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
