A Measurement Method Considering Both Phase Noise and Full Frequency Stability

The current mainstream phase noise measurement systems use the reference signal and the measured signal to achieve phase quadrature control after mutual locking, and then through phase information sampling, algorithm processing to get the single-sideband phase noise curve. A novel digital linear phase comparison method - DLPC can automatically keep the orthogonal phenomenon of the signal under test without lock processing. Therefore, it is easy to use and work more stable. This method is different from the traditional method, including the digital DMTD. That is, the frequency stability sampling time corresponding to the deviation of the carrier frequency from 1 Hz to 1 MHz or 10 MHz in the usual phase noise measurement is also the stability index from 1 second to 1 ps or 0.1 ps, respectively. The frequency stability measurement of DLPC can cover the period from the signal carrier frequency to the unlimited time. The new method works more stably, especially in the case of noise interference and poor stability of the measured signal, and lock loss will not occur. At the same time, the new technology can measure the phase noise in time domain and frequency domain simultaneously, and can fully reflect the noise essence of frequency source and the effect of noise influence.