Noise analysis of non-autonomous radio frequency circuits

Abstract

Considers the important problem of noise analysis of non-autonomous nonlinear RF circuits in the presence of input signal phase noise. We formulate this problem as a stochastic differential equation and solve it in the presence of circuit white-noise sources. We show that the output noise of a nonlinear non-autonomous circuit, driven by a periodic input signal with phase noise, is stationary-not cyclostationary (as would be predicted by traditional analyses). We also show that effect of the input signal phase noise is to act as additional white noise source. This result is derived using a full nonlinear analysis of the problem and cannot be predicted by traditional linear analysis-based techniques. Input signal phase noise can be an important portion of the overall output noise of the non-autonomous circuit. In our opinion, existing analyses have not considered this effect in a rigorous manner. We also relate this solution to results of the existing nonlinear time-domain and frequency-domain methods of noise analysis and point out the modifications required for the present techniques. We illustrate our technique using an example.