I used the holidays to do a set of tests of the SDR-1000's frequency stability and phase noise (I got temporary access to an Agilent phase noise measurement system to make those possible.
I was able to measure the frequency offset, warmup drift, and frequency-vs.-temperature performance of the SDR-1000 with its stock oscillator. I also did a similar set of tests of a prototype Reflock-II frequency stabilizer locking a 100MHz low-jitter oscillator to a 10MHz TCXO. I'm not particularly happy with the phase noise results; due to time constraints we didn't have a chance to properly design the interface and I think there are some external factors that make the numbers look worse than they are. I hope I'll get a chance to play with the phase noise box again and get some better results. But there's still a useful comparison of the noise of the standard 200MHz oscillator versus an external 10MHz reference multiplied by 20; you can really see how the phase noise is increased by multiplication. Anyway, the results are at http://www.febo.com/geekworks/sdr1k. 73, John
