Injection locked differential ring VCO

This paper proposes an injection locked four stage differential ring voltage controlled oscillator (VCO), in which in-phase and quadrature phase of the reference signal is injected after the first stage, for both frequency multiplication and division. The free running frequency of 4-stage differential VCO is 485MHz. Frequency Multiplication is carried out by injecting a reference frequency of 1.25GHz the corresponding output frequency observed is 1.25GHz. Frequency division is carried out by injecting a reference frequency of 242MHz and a corresponding output frequency of 250MHz is observed.