optical phase-locked loops that begins with sections discussing components such as lasers and photodetectors and finishing with homodyne and heterodyne loops. Starting with a historical overview, presenting analog, digital, and optical PLLs, discussing phase noise analysis, and including circuits/algorithms for data synchronization, this volume contains new techniques being used in this field. Highlights of the Second Edition: Development of phase-locked loops from analog to digital and optical, with consistent notation throughout; Expanded coverage of the loop filters used to design second and third order PLLs; Design examples on delay- locked loops used to synchronize circuits on CPUs and ASICS; New material on digital dividers that dominate a frequency synthesizer's noise floor. Techniques to analytically estimate the phase noise of a divider; Presentation of optical phase-locked loops with primers on the optical components and fundamentals of optical mixing; Section on automatic frequency control to provide frequency-locking of the lasers instead of phase-locking; Presentation of charge pumps, counters, and delay-locked loops. The Second Edition includes the essential topics needed by wireless, optics, and the traditional phase- locked loop specialists to design circuits and software algorithms. All of the material has been updated throughout the book.