Injection-locked frequency divider with a wide injection-locked frequency range

摘要

An injection-locked frequency divider includes a signal injection circuit and colpitts VCO. The signal injection circuit is for injecting an injection signal. The colpitts VCO includes first and second transistors, first and second LC tank circuits and a cross-coupled transistor pair. The first terminals of the first and second transistors receive the injection signal. The first and second LC tank circuits are for determining resonance frequency of an oscillation signal of the colpitts VCO. The cross-coupled transistor pair includes third and fourth transistors. The control terminals of the third and fourth transistors are respectively coupled to first terminals of the fourth and third transistors. The first terminals of the third and fourth transistors are respectively coupled to a first terminal or control terminal of the first and second transistors for providing an equivalent negative resistance. The injection signal and oscillation signal are mixed in frequency to generate differential output signals.