An efficient and robust method for ring-oscillator simulation using the harmonic-balance method

A novel approach for simulating the periodic steady state of ring oscillators with the harmonic-balance method is described. This approach is efficient and robust compared with traditional approaches. The key idea exploited is the structure of the ring oscillator, in which the properties of a single delay cell are used to simulate the response of the overall oscillator. The proposed method yields an algorithm that is computationally efficient and readily converges for a wide variety of single-ended and differential ring-oscillator circuits.