Am 21.12.2010 21:41, schrieb Rick Karlquist:
No, this is a fallacy because phase noise adds coherently, so that each doubler adds 6 dB and each tripler adds 9.54 dB. There is no way to get around 20 LOG N, no matter how you implement the multiplier even if you add a tripler output to a quadrupler output, where phase noise also adds coherently.
Yes, it adds coherently because it stems from the same source.
It is easier to see in the time domain: 1ps of jitter on a 10 MHz carrier, when multiplied to 100 MHz is still 1 ps of jitter, just look at the zero crossings. But at 100 MHz, the jitter percentage of 1 ps to the 360° is 10 times as bad, because the 360 degrees/s have shrunk. So, a phase detector will give 10 times the output voltage or 20 dB more power. No way around this. Gerhard, dk4xp _______________________________________________ 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.
