Cadence Design Systems, Inc.

Xiaolue Lai

Yu Zhu

Xiaohui Wang

Dan Feng

An apparatus and method for identifying an optimal harmonic number of a circuit are disclosed. In a simulation of the circuit, a periodic input waveform up to a particular number of periods is applied to the modeled circuit and an output waveform is obtained in response. In response to detection of a steady state response of the output waveform, embodiments simulate the circuit by applying an additional period of the periodic input waveform and obtaining the output waveform corresponding to the additional period of the periodic input waveform. A time domain power value and a frequency domain power value are calculated using the output waveform corresponding to the additional period of the periodic input waveform. Embodiments detect a harmonic of the output waveform corresponding to the additional period of the periodic input waveform at which the time domain power value and the frequency domain power value converge with each other.

Automatic harmonic number identification for harmonic balance analysis

In a circuit simulation tool in a computer system having one or more computer processors and computer-readable storage, a method for characterizing a driven oscillator circuit having an oscillator coupled to a time-varying input signal includes retrieving information provided in a circuit description of the oscillator circuit. The method also includes forming a frequency-domain harmonic balance equation for the oscillator circuit using the retrieved information provided in the circuit description of the oscillator circuit. The harmonic balance equation includes a first differential operator in a frequency domain of the input signal and a product of a differential operator in a second frequency domain of the oscillator and a frequency variable of the oscillator. The frequency variable is independent of the frequency domain of the input signal. The method further includes solving the harmonic balance equation to obtain a waveform description of the oscillator circuit.

Method and system for steady state simulation and noise analysis of driven oscillators

An apparatus and method for performing periodic noise (Pnoise) simulation with full spectrum accuracy is disclosed herein. Noise contributions of a circuit under consideration are identified and separated for different computation treatment. The different computation treatment results in computational efficiency without sacrificing accuracy of simulation results.

Shooting Pnoise circuit simulation with full spectrum accuracy

In one embodiment of the invention, a method and a system for phase noise analysis of oscillators is provided using frequency aware perturbation projection vector techniques. The method and system includes performing steady state analysis on the oscillator by generating an augmented Jacobian matrix. A transfer function for frequency deviation is extracted for the augmented Jacobian matrix for a predetermined frequency range including the oscillation frequency of the oscillator. The phase noise is predicted based on the extracted transfer function.

Phase noise analysis of oscillator circuit designs

Embodiments may include methods, systems, and computer-readable storage mediums that may be used to simulate phase noise for an oscillator circuit. In some embodiments, a method of simulating phase noise for an oscillator circuit may include providing an oscillator circuit description. A time-domain representation of a small signal phase noise of the oscillator circuit description may be determined. A shooting Newton matrix representation of the time-domain representation of the small signal phase noise may be generated. The shooting Newton matrix representation may be augmented to include a phase-shift factor and a pinning equation. The augmented shooting Newton matrix representation may be solved to determine a signal output of the oscillator circuit.

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San Jose, CA, United States of America

Xiaolue Lai