A. V. Korolev1, S. G. Rykov2
1, 2 JSC «All-Russian Scientific Research Institute of Radio Engineering» (Moscow, Russia)

1 teleret@mail.ru, 2 brig001@mail.ru

Improving the characteristics of modern digital-to-analog converters (DAC) and direct digital synthesizers (DDS) has significantly expanded the capabilities of generating signals in the RF range for information transmission and radar systems using direct digital synthesis methods in the design of phased array antennas and stimulated the study of phase noise in such systems. At the same time, the addition of output oscillations of multichannel digital synthesis circuits (MDSC), which include DAC and DDS, does not always lead to the expected reduction in noise level. It would be of interest to find out whether this effect is characteristic of modern DAC and DDS. The measurements of two MDSC phase and amplitude noises when summing the channels show that the spectra of both phase and amplitude noise of the combined output oscillations contain correlated components that must be taken into account when noise modeling. The influence of the phase noise of MDSC clock distribution circuitry on the phase noise of the combined output oscillations has been revealed. The calculated relationships obtained in this work for the power spectral densities of amplitude and phase noise make it possible, with good accuracy for engineering practice, to model the change in noise characteristics at the output of combined low noise oscillation sources in the presence of amplitude noise, the power spectral density of which is significantly higher than the spectral density phase noise power.

Korolev A.V., Rykov S.G. Phase noise experimental study of multichannel digital synthesizers with combined digital-to-analog converter outputs. Antennas. 2024. № 5. P. 37–46. DOI: https://doi.org/10.18127/j03209601-202405-04 (in Russian)

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