WIRELESS CLOCK REGENERATION AND SYNCHRONIZATION

摘要

A method and apparatus are described for regenerating a local clock within a wireless module and synchronizing the local clock with a wireless host clock. For one embodiment, the wireless module generates a local clock, counts the cycles of the clock during a common timing reference period maintained wirelessly between the wireless module and the host, receives a count of the host clock during the same common timing reference period, and adjusts the local clock signal based upon a comparison of the two counts. For one embodiment, the wireless module further receives timing references from the host and, in addition, receives packets of audio samples from the host accompanied by a timestamp, the timestamp based upon the host timing reference, and outputs the audio sample at the time designated by the timestamp.

主权项

1. A method comprising:
receiving at a wireless module a signal representing a host clock having a host clock frequency; generating a local clock signal having a local clock frequency within the wireless module; setting the local clock frequency based on the host clock frequency; establishing a timing reference period common to the wireless module and a host to form a common timing reference, wherein the common timing reference is maintained wirelessly over a wireless link by receiving at least two signals representing beacons as control signals, and establishing the timing reference period as a beacon period between the two signals representing the beacons; receiving, from the host over the wireless link, host clock count during a period of the common timing reference; and adjusting the local clock signal based upon the host clock count to form an adjusted local clock signal.