Phase noise: whether identical at all nodes in free-running oscillator circuit

Many years ago it was analytically demonstrated that phase noise in free-running oscillators might be different on the different circuit nodes. Recently this result was questioned. It was claimed that phase noise is identical at all nodes, and characterised by a single scalar constant for white noise sources. Using the time domain Monte Carlo method, which is the only method which does not treat the large signal and the noise signals separately, it is demonstrated that in free-running oscillator circuits the phase noise could be different on the nodes of the circuit and cannot be represented by a single scalar constant. This result is confirmed by simulations performed in the frequency domain using the conversion matrices method.