Noise Modeling in Voltage-Controlled Oscillators in SPICE-Based Programs

This article describes the problem of phase noise modeling in circuit modeling programs using spice models, such as Micro-Cap 12. Such programs use “ideal” models that may not take into account the real noise of the simulated elements. For example, such an element is a voltage-controlled oscillator (VCO), which is simply a mathematical dependence with a changing frequency when exposed to an external voltage. The article discusses a method for obtaining the phase noise of elements by additional action on the input of the generator, using a pseudorandom value, with a distribution that repeats the dependence of the phase noise on the frequency of the oscillator.