Implications of Esoteric G-0Rb atomic clock


The latest TAS (March 2008) has an excellent piece by Robert Harley: a review of the Esoteric G-0Rb Master Clock Generator, with sidebars on the history and significance of jitter. This Esoteric unit employs an atomic clock (using rubidium) to take timing precision to a new level, at least for consumer gear. It's a good read, I recommend it.

If I am reading all of this correctly, I reach the following conclusions:

(1) Jitter is more important sonically than we might have thought

(2) Better jitter reduction at the A-D side of things will yield significant benefits, which means we can look forward to another of round remasters (of analog tapes) once atomic clock solutions make it into mastering labs

(3) All of the Superclocks, claims of vanishingly low jitter, reclocking DACs -- all of this stuff that's out there now, while probably heading in the right direction, still falls fall short of what's possible and needed if we are to get the best out of digital and fully realize its promise.

(4) We can expect to see atomic clocks in our future DACs and CDPs. Really?

Am I drawing the right conclusions?
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Showing 1 response by serus

Rubidium is not necessary for timing accuracy, but it makes sense that a commercial rubidium reference oscillator would pay special attention to close-in phase noise in the vicinity of the main carrier, which is what's improtant in regard to jitter.
To put the frequency accuracy issue to rest, here are the facts. Standard (i.e. cheap) crystals are guaranteed within 100 PPM (parts per million) in the proper circuit. Add another 100 PPM for extreme temperature/humidity and circuit voltage variations. The total is 200 PPM or 0.02% of frequency accuracy. For a 1 KHz signal it will be off by 0.2 Hz. Even an acute dog wouldn't be able to tell the difference...
It's a joke when some manufacturers offer an "upgrade" to a TCXO option. How about upgrade to a low-noise oscillator? I'll take that option any day!