[time-nuts] What is the best way to multiply a 10 Mhz

[Gerhard Hoffmann]

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