> I may need a Dual Mixer Time Difference (DMTD) instrument, to measure > picosecond changes in electrical length in a coax plus amplifier time > reference signal distribution system with total delays in the hundreds > of nanoseconds, currently operating at 10 MHz (sinewave), but with 100 > MHz likely at some future date. > > What DMTD instruments are commercially available? A google search was > not successful - all noise no detectable signal, probably because DMTD > instruments are not that common, and many people build their own.
We use dual-mixer systems in our primary time scale and also to calibrate and evaluate oscillators and timing hardware. So far as I know, the only units that are commercially available are made by Timing Solutions, which was recently acquired by Symmetricom. There are a number of different configurations, depending how how many devices you want to measure, whether they all run at the same frequency, etc. It is possible to build these devices on your own, but it is not trivial to get pico-second resolution and stability. Almost everything is temperature sensitive at this level of resolution. Judah Levine Time and Frequency Division NIST Boulder _______________________________________________ questions mailing list [email protected] https://lists.ntp.org/mailman/listinfo/questions
