Thanks - here is the SiTime Whitepaper on Jitter and Phase Noise - they are not the same thing. Measured in different ways. Phase noise measures are quoted in decibels not ps. The guy who wrote that doesn't know much. And there is more then one kind of jitter.
http://www.sitime.com/support2/documents/AN10007-Jitter-and-measurement.pdf
As you can see from figure 6. on page 8 - Phase Noise Plot
TXCO and OXCO clock manufacturers Like NDK and Crystek quote all Phase Noise in decibels.
Crystek CCHD-957 Datasheet:
http://www.crystek.com/crystal/spec-sheets/clock/cchd-957.pdf
In think you might have a point, but let me tell you my own understanding.
I think that both quantities are related, and that is what your paper says. 0 phase noise means 0 jitter and vice versa. But the chart in db/hz is interesting in that it characterizes the energy distribution over the frequency domain and tells you how that noise will affect the sound. Still, if jitter is miniscule, its energy distribution will not matter because you will not hear any sound degradation.
The phase noise is assumed to have gaussian distribution, meaning its peak value is around 7 times the stated global figure, which is a standard deviation. Again, the db/hz distribution indicates the frequency contents of noise plus the carrier. By integrating this chart, you get a global figure for phase noise and jitter. If everything is normal in the statistical sense, low jitter will translate into a satisfying frequency distribution graph.
In my understanding, you are right somehow in the sense that the low frequency contents could still be significant, for instance let's say -90db at 20hz. In an audio signal, it will translate into a degradation of the bass.
For audio transmission over usb, does the low frequency part of phase noise (and the rest of the noise, by the way) matter? Probably because asynch usb has no error correction (just transmission speed adjustments determined by the receiver) and jitter in the input means jitter in the output. In case of a ddc, it means jitter in the signal to the dac. But to dig deeper, that speed adjustment thing will create ponctual jitter in itself. So the ddc has to reclock the data because it will have high jitter anyway. So we are led to considerations like how does that the overall gaussian jitter affect the ability of the ddc to output a jitter-free signal. I can't answer that question.
But i believe asynch usb to transmit audio in not the best protocol for sure. It is just convenient, It seems very hard to decode the signal to obtain a jitter free output to the dac. And it prone to signal contamination.
In any case, i should get an f-1 board soon. In really like the overall design of this ddc. The fact that both the receiving and transmitting part are well isolated from each other and that they each have their own xmos processor.
Sigh.