Importance of Clock Signal in Modern Microelectronic Systems

Clocking is an important and challenging topic in both academic research and engineering practice. Integrating circuit (IC) clocking is closely tied to the two functions in modern chip design: communication and computation. When a clock signal is used in an electronic system, it involves two groups of engineers: designers of the clock generator and users of the clock signal. Today's typical electronic systems contain millions of electrical signals. In modern systems, there can be hundreds of clock signals operating in a chip simultaneously to achieve sophisticated functions. There are two trends in designing today and tomorrow's electronic systems: integrating more functional blocks into a system and increasing clock frequency (for faster information processing). Modern electronic system design calls for a new clock source that is flexible in its ability to generate frequency. This is a new requirement commanded by the ever-increasing complexity of modern systems.