Abstract: A method and apparatus for controlling the phase and frequency of the local clock of a USB device, the apparatus comprising circuitry for observing USB traffic and decoding from the USB traffic a periodic data structure containing information about the frequency and phase of a distributed clock frequency, and phase and circuitry for receiving the periodic data structure and generating from at least the periodic data structure a local clock signal locked in both frequency and phase to the periodic data structure. The circuitry for receiving the periodic data structure and generating the local clock signal can generate the local clock signal with a frequency that is a non-integral multiple of a frequency of the periodic data structure.