56 connection between internal noise currents and phase and amplitude fluctuations were derived. <...> Simple formulae for these oscillators PM and AM noise calculation are obtained. <...> Power spectral densities of PM and AM noise were calculated taking into consideration both thermal noise of feedback loop and all other sources of wideband noise. <...> It is shown that contribution of the active devices noise is small enough to ignore it for approximate evaluation of PM noise. <...> Results of these two oscillators PM and AM noise comparison are presented. <...> These results can be used to solve the problem of RC oscillators circuits sideration their noise properties. choice taking into conFLUCTUATIONS IN THE QUADRATURE RING OSCILLATORS WITH PLANIMETRIC CHAINS INTERSTAGE COUPLING V.N. <...> Kuleshov, National Research University “Moscow Power Engineering Institute”, professor , Dr.Sci. <...> Kochemasov, National Research University “Moscow Power Engineering Institute”, postgraduate; KochemasovDV@gmail.com Keywords: ring oscillator, quadrature fluctuations, fluctuations of the phase, amplitude, phase difference and the difference of the oscillation amplitudes, the spectral power density. <...> Results of investigation of internal wideband noise influence on quadrature oscillator (QO) using single tank resonators in ring structure performance are presented. <...> Simple formulae for power spectral densities (PSD) of phase and amplitude fluctuations are derived using slowly varying amplitude approach. <...> In addition to these results the formulae for output oscillations phase difference and relative amplitude difference are derived. <...> These PSD are necessary to estimate internal noise influence on the QO performance. <...> An example of quantitative analysis of the phase and amplitude fluctuations in the particular QO model is presented <...>