Hi You get into all sorts of issues trying to estimate tempco. You have time lags and gradients that make it a very messy process. Toss in measurement based on small range temperature swings (like from a HVAC system) …. it’s a mess. If the OCXO is a typical modern part and it’s been on power for a couple of weeks, why bother?

Hi, There is trivial ways to estimate phase and amplitude of a sine using linear methods. I saw however none of these properly referenced or described. It would have been good to see those approaches attempted in parallel on the same data and compare their performance with the proposed approach.

pll offset: 0 pll frequency: -28.451 maximum error: 0.1055 estimated error: 3e-06 kernel status: pll ppsfreq ppstime ppssignal nano pll time constant: 6 precision: 1e-06 frequency tolerance: 500 pps frequency: -28.451 pps stability: 0.012085 pps jitter: 0.007 calibration interval

I later talked to a geologist who knows the Danish underground well, and he estimated I would have needed to drill to at least 25m depth to escape seasonal temperature-changes and cited a research paper from the 1950'ies where the did precisely that experiment.

Collins uses a trapezoid approximation throughout and thus over-estimates the noise contribution of low-gain stages, which are the first stages thus contribute to a relatively large error in the calculation.

Their turn around time estimate is 4 weeks. JLT> Hopefully, I will have it back by first part of November. JLT> I found the folks in Oak Ridge very friendly and helpful. The lady I spoke JLT> with offered to try to find a manual for the 7081 but did not have any.

Perhaps the DCI specifications had been estimated very generously, saving time, instead of trying to validate to the lowest possible inaccuracy. My understanding of the instrument is, that its main purpose was for military use (because of the broad env. temp. range) and for DCV and ACV mainly.

By just looking at very rough estimates of rates per hour, these numbers were somewhere around 2500 Tree Swallows during the afternoon and 3000 Chimney Swifts for the day.   The sky was filled with these birds all going east to west.  As were the dragonflies. 

It is estimated that the global population of Rusty Blackbirds has declined by an astounding 85-95% since the mid 1990s.

I must say I never thought too much about this sort of thing until a few years ago when the Simsbury Calliope Hummer was allowed to freeze to death in the name of letting Nature take its course, even though the bird was, by all estimations, perfectly healthy until the really frigid cold arrived.