What exactly is Femto clocks?

[jilleriran]

I saw a lot of buzzwords around Femto clocks in High-end DACs  so now i'm just wondering what is it? What it can do? or Is this just snake oil?

 

[DrKC]

It's not snake oil in the sense that a stable, accurate clock is important for clocking bits for conversion.  I might have some doubts as to the claims.  If you're familiar with terms like micro and nano then pico follows and then femto.  that's 10 raised to the -15 power.  A tiny amount to be sure.  I've worked with gps-disciplined oven-based oscillators that achieved 10 to -9 or -10 in terms of accuracy ergo stability.  So, maybe there is a magical new technology that allows for femto accuracy on a plain old pcb.  The telcom and satellite industry will be thrilled.