Injection Locked Frequency Dividers
High-speed frequency dividers (a.k.a prescalers) are essential building blocks in wireless and wireline communications for functions such as frequency synthesis, quadrature signal generation, and multiplexing (MUX/DEMUX). For example, a prescaler is one of the major components in a phase-locked loop (PLL) (see Fig.1), which is widely used as frequency synthesizers in a radio transceiver. Currently, static or dynamic digital dividers are commonly used in RF/microwave PLLs . They have simple structures, large bandwidth, and good robustness over process variations . As the radio operation frequencies increase beyond the low GHz range, however, power consumption of digital dividers becomes a problem. It becomes increasingly difficult for them to meet a reasonable power budget. This is especially challenging in low-power mobile applications. Furthermore, due to large power dissipation, high-speed digital dividers can also introduce considerable noise degradation. Therefore, a frequency divider with better power efficiency is urgently needed.