On 9/26/20 8:10 AM, John Ackermann N8UR wrote:
We know that phase noise scales with frequency, so if you multiply
frequency by 10 you get a 20 dB increase in noise.
What I don't fully understand is how that relationship works with other
than simple multiplication/division.
For example (and my real life concern), if I have an analog to digital
converter that is clocked at 122.88 MHz and know the phase noise of that
clock signal, what do I know about the effective phase noise when the
ADC is receiving a signal at, e.g., 12.288 MHz?
To a first order, the ADC is like an ideal multiplier/mixer - phase
noise on the clock contributes to phase noise on the sampled data by
reciprocal mixing, just like a mixer.
In other words, if I were to measure the phase noise at the output of
the ADC when fed a high-enough quality 12.288 MHz signal, would I see
something like the 122.88 MHz phase noise, or something better due to
the scaling by 10?
Thanks!
John
_______________________________________________
time-nuts mailing list -- time-nuts@lists.febo.com
To unsubscribe, go to
http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
and follow the instructions there.
_______________________________________________
time-nuts mailing list -- time-nuts@lists.febo.com
To unsubscribe, go to
http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
and follow the instructions there.
