Michael wrote:
My concern about the BPSK, and breaking my Spectracom oscillator, is really
centered on loosing my NIST traceable reference oscillator. I don't care one
bit what time of day it is. * * *
So while an HP-117 or a Spectracon 8160 oscillator phase locked to
WWVB is "by definition" an NIST traceable standard so long as it is
in lock and
you have a valid lock history, a GPS unit, even though it may be
just as stable an
oscillator, isn't an NIST traceable standard without a whole lot of
equipment to
validate that NIST and the GPS system are in sync. * * *
For all you metrology guys out there, has any of this recently changed?
These NIST links should get you started:
http://nist.gov/traceability/
http://tf.nist.gov/general/pdf/2297.pdf
http://www.nist.gov/pml/div688/grp40/gpsarchive.cfm
<http://www.google.com/url?sa=t&rct=j&q=&source=web&cd=1&ved=0CEEQFjAA&url=http%3A%2F%2Ftf.boulder.nist.gov%2Fgeneral%2Fpdf%2F1502.pdf&ei=CmRtT9fSB4ji0gGAm7n_Bg&usg=AFQjCNGO0uxF4gdRhld-L8PEERwEmaGgGg>
Note that only *measurement results* are "traceable" -- not local
standards. There is no such thing as a "NIST traceable
standard." And even with a WWVB reference, one needs an "internal
measurement assurance program" to support a claim of traceability for
the measurements that one makes. Just having an HP-117 or Spectracon
8160 is not sufficient to claim NIST traceability for one's
measurements. Note that less than 1% of claimed "NIST traceability"
really is traceable to NIST. For all the stuff on eBay that claims
to be "NIST calibrated" (Really? Did you take that to Boulder for
calibration?) or "NIST traceable," only a negligible amount of it really is.
Best regards,
Charles
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