Dear time-nuts My name is Marco Ferra. I'm doing research on an electrical metrology laboratory in Portugal, and I'm conducting a study on how to establish tracebility to frequency using one (or more) GPSDO's. I came across febo.com's site and this mailing list after searching the net. Let me tell you what I'm doing.
I have put side-by-side two GPS receivers, one HP58503 (now owned by Symmetricom I believe) and a Fluke 910R, both with it's own antenna. Both antennas are separated by about 100 meters. I'm tracking the 10 MHz output of both GPS receivers with a Fluke PM6681R Counter. I'm using the internal Rubidium oscillator of the counter and using channels A and B for the measurements. Each 10 seconds, I'm recording the frequency on channel A, B, and the phase (in degrees) between the two signals. I have resolution on the phase by 1/10th of degree. With the phase, I can get the time differente in nano-seconds between the two signals: =phase(degress)/(360*10000000)*10^9 I'm putting 10000000 Hz has a nominal frequency for the calculation, I'm not sure if should use the frequency recorded on channel A or B. Then I calculate the time difference, the TIE (ns), the Delta Tie (ns) accumulative, and then the Delta f (it's equal to Delta TIE (ACC) / measurement time (could be 10, 20, 30 secs)). Please take a grasp at page 4 of http://www.pendulum-instruments.com/Assets/download/accurate_calibration _article.pdf Given these two GPSDO's, and given the very small Delta f, I can assume that both GPSDO's are functioning proprely (could I indeed?). But I'm not sure how I can get tracebility to national standards, to NIST, for example, on the 10 MHz output frequency. Perhaps it's difficult, but I need a solid proof that my 10 MHz output is traceble to a primary laboratory. I have seen that you all have a vast experience in this area, and perhaps we could work together to gather good results and achive this goal. Sincere regards, and thank you for reading, Marco _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
