Frequency Dividers

Summary

In this chapter we have discussed different frequency division techniques and explained the tradeoffs and application of each method. We explained that at high frequencies (e.g., higher f _T /5) than analog techniques become more attractive than digital methods. Among all analog frequency dividers, injection-locked frequency dividers can potentially operate at a higher frequency and with a lower power consumption. The reason is hidden in the nature of the injection-locked frequency dividers: An ILFD is an oscillator capable of operation at frequencies approaching f _max of the technology.

We also developed a general theory for injection-locked frequency dividers which elucidates the frequency division mechanism of an ILFD based on intermodulation of the input and output signals. This model predicts for the first time the possibility of injection locking failure at large incident amplitudes. It also provides direct design insight on how to maximize the locking range of an ILFD. Finally we derived a first order differential equation which describes the noise performance of an ILFD.