Analog electrical elements such as mixers, filters, transfer oscillators, isolating buffers, dividers, and even transmission lines contribute technical noise and unwanted environmental coupling in time and frequency measurements. Software defined radio (SDR) techniques replace many of these analog components with digital signal processing (DSP) on rapidly sampled signals. We demonstrate that a relatively low-cost, commercially available SDR is capable of time and frequency metrology competitive with other methods. We discuss the scalability of a SDR-based system for simultaneous measurement of many clocks. We show that the inherent frequency agility of SDR allows for the measurement of ultra-stable oscillators at widely different frequencies, such as those linked to ultra-stable lasers and optical clocks.
Review of Scientific Instruments
clocks, oscillators, precision measurement, software defined radio, time and frequency metrology