A Novel Phase-Noise Module for the QUCS Circuit Simulator. Part II : Noise Analysis

Torsten Djurhuus; Viktor Krozer

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arXiv · 2603.07828

A Novel Phase-Noise Module for the QUCS Circuit Simulator. Part II : Noise Analysis

Torsten Djurhuus·Viktor Krozer

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Abstract

The paper documents the implementation of a novel phase-noise analysis module within the open-source QUCS circuit simulator environment. The underlying algorithm is based on a rigorous, unified time-domain methodology of (coupled) oscillator noise-response, recently proposed by the authors. The theoretical approach used to develop this model is entirely unconstrained by any empirical and/or phenomenological modelling techniques, such as e.g. LTI and LTV theory, and this differentiates it from all prior proposals on this topic. The paper introduces important, and previously unpublished, extensions to this framework, in the form of novel unified closed-form expressions for both the amplitude and phase-amplitude correlation response of a general coupled oscillating circuit perturbed by noise. The research discussed herein has many important scientific and industrial applications w.r.t. predicting, synthesizing and optimizing the performance of noise-perturbed free-running and coupled autonomous circuits operating under large-signal steady-state conditions. These timing circuits are ubiquitous in all modern communication and remote-sensing systems and the developed simulation tools will prove to have great impact in various areas of industrial circuit design. This paper represents second part of a two-part series with the first part discussing the implementation of the underlying steady-state analysis module. The open-source simulator, discussed and developed herein, applies advanced state-of-the-art stochastic modelling techniques, in-order to produce noise simulation tools with capabilities and scope which, in many areas, exceed what is found in the commercial EDAs currently on the market.

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Torsten Djurhuus, Viktor Krozer. 2026-03-08. A Novel Phase-Noise Module for the QUCS Circuit Simulator. Part II : Noise Analysis. https://arxiv.org/abs/2603.07828

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