[time-nuts] Comparison of Logic Standards for Clock Distribution

M. Warner Losh imp at bsdimp.com
Thu Oct 26 13:57:47 EDT 2006


In message: <4540002B.3050807 at xtra.co.nz>
            Dr Bruce Griffiths <bruce.griffiths at xtra.co.nz> writes:
: But the input voltage noise of the MAX477 is 5nV/rtHz, the corresponding 
: value for a discrete transistor circuit may be as low as 1nV/rtHz.

rtHz is a new one for me (I'm mostly a software dude).  A quick google
search shows that this appears in lots of spec sheets as a measure of
noise (which I get from this context), but what is that exactly?

http://www.ic-designs.com/ICDTechBrief1.pdf gives a nice detailed
account of how to calculate this number (V/RTHZ it says), but doesn't
define the base unit.  I get the 'Hz' part, but not the 'rt' part.
Can someone provide a good reference?

Warner





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