A transposed frequency technique for phase noise and frequency stability measurements

The digital signal processing has greatly simplified the process of phase noise measurements, especially in oscillators, but its applications are largely confined to the frequencies below 400 MHz. We propose a novel transpose frequency technique, which extends the frequency range of digital noise measurements to the microwave domain and beyond. We discuss two basic variations of the proposed noise measurement technique, one of which enables characterization of phase fluctuations added to the passing signal by the particular microwave component, for example by an amplifier, while another one is intended for measurements of phase fluctuations of the incoming signal itself.