Digital waveforms, accurate timing or spur-free echoes require clean frequency clocks or local oscillators. Tremendous developments are allowing “better than yesterday” solutions in frequency generation, they can be crystal-based or optically generated but they all require at a point in time to be measured. Besides low noise sources, amplifiers and frequency translating devices can also be tested through different techniques, more appropriate than a traditional absolute phase noise approach. The DCNTS provides the lowest noise floor of the industry while the NXA combines ease of use and great flexibility. All solutions are also applicable to ultra-long life PN9000, well represented through the world.