Frequency synthesis using non-integral subharmonic injection locking

Non-integral subharmonic injection locking behavior is presented in this paper. It was found that BJT oscillators can lock to its non-integral subharmonic such as 2/3, 3/4, 2/5 etc. In addition to the even and odd integral subharmonics. A feedback model is used to explain the effect. Applications of non-integral subharmonic injection locking can be found on the stabilization of a high frequency oscillator by a low frequency source, and on high frequency synthesis from a low frequency source in which the frequencies are non-integrally related. This will greatly increase the flexibility of injection-locked oscillator design and reduce the circuit complexity for mobile communication.<>