Research Of Phase Noise Measurement Based On Phase Difference Group

Conventional phase noise measurement system is built on the base of phasecomparison between two signals with the same frequency. Different frequency signalsmust go through a complex frequency conversion part to measure their phase noise.This paper made the phase relations between signals with different frequency as astarting point, and then found that phase different change of a periodic pattern. Usingthis rule can directly compare the phase between signals of different frequency andextract phase noise information, then the single-sideband phase noise spectral densitycan be obtained after Fourier transform.First, this paper went on with traditional phase noise measurement system,analyzed some methods of phase noise measurement, and pointed out their advantagesand disadvantages. Second, we discussed the directly phase comparison between twosignals with different frequency, and Introduced “group-phase quantum” and otherimportant concept in detail. Third, we put the block diagram of phase noisemeasurement system based on phase difference group forward, and analyzed themodules of the hardware circuit. With PC software, we had made several experiments toprove the correctness of the system. Finally, we discussed The noise floor of this systemand pointed out the improved methods.Phase noise measurement system based on phase difference group not only callsoff the need for a general phase noise measurement system in the frequency conversionpart, but also makes the system simple and cost saving.