US Patent 7814376 Method and apparatus for frame delineation

A frame delineation mechanism which alternately considers even and odd sync pattern position possibilities. With the addition of toggle logic, each of 66 possible states of even and odd alignment are exhausted in turn, odd, followed by even, followed by odd and so on, providing synchronization more quickly than known mechanisms. Additionally, faster convergence is reached due to the use of an exhaust register which keeps track of those alignment states that were tested but did not provide synchronization. Until synchronization is acquired, the states indicated in the exhaust register are ignored in further attempts to acquire synchronization.