For frequency measures you can overcome the single-shot resolution by using multiple start and stop locations and process the estimates. BTW, some counters use quite different approaches for triggering and routing their TI measures and their frequency measures, to such degree that frequency trimming requires separate calibration.

Your OCXO likely had a pair of events that caused the aging estimate to get very low. Bob On Jun 28, 2013, at 8:16 AM, Mark C. Stephens wrote: > I noticed my Z3815A was show 0ns (zero) for predicted uncertainty tonight. > > Is there something wrong or is its predicted holdover uncertainty below measureable (displayable) value?

You could clearly see the separation into two lines for the clock and that gave us a hint, which correlated well with BER estimates on the high-speed links. If you look around, you will find several companies patenting their field programmable device, and it's infrastructure more on the concept level than the actual technology in the crystal.

> > "The total number of QCU's produced by all manufacturers during the war is difficult to ascertain; estimates have ranged from 30 million to over 70 million QCUs produced by American manufacturers between 1941 and 1945." > > McGahey, Dissertation, "HARNESSING NATURE'S TIMEKEEPER: A HISTORY OF THE PIEZOELECTRIC > QUARTZ CRYSTAL TECHNOLOGICAL COMMUNITY (1880

It's important to understand these so that their effect can be estimated and sometimes mitigated. > > > As an aside, I work low frequency RF transmissions on 136 Mhz, and > very narrow bandwidth. Can a soundcard be locked to GPS instead of > its own internal crystal for precise frequency output?

The rubidium runs open loop and the BTE keeps track of the offset and the drift rate from "BTE time" (which is synthesized from all available sources -- however many CDMA signals it is receiving, plus any wireline telco timing signals and the PRS10 -- using a proprietary algorithm to estimate the reliability of each source and outputting BTE time and frequency

Magenta is the receiver estimate of its time error (both in nanoseconds). The Trimble Resolution-T receivers report a similar "local clock bias" value, but they don't seem to document what it actually is...

This kind of strong prior assumption is why sinusoidal estimators and PLLs are able to extract tones with precision far beyond what you would expect from taking a DFT from equivalent amount of data.

The advantage of the incandescent is that you can estimate the temperature fairly accurately and thus come up with the noise by calculation. We did the build as part of a radio club meeting back in the 60’s.

But you can see why people would like PN ranging - it takes NO power from the carrier, so you can get a really good doppler estimate. In reality, of course, you can post process to remove the BPSK data (just like removing the PN ranging) and essentially get all the power back in the carrier. But you can really only do that on the downlink.