US Patent 7285946 Pattern trigger in a coherent timebase

A method and apparatus for acquiring a signal employing a coherent timebase are provided. The method comprises the steps of defining a pattern length count of a repetitive pattern in a signal to be acquired, defining a number of samples per unit interval, and providing data strobes synchronous to a coherent timebase. An arbitrary one of the data strobes is designated as a timing for a potential trigger. A number of subsequent data strobes is counted in accordance with the pattern length count times the samples per unit interval and a portion of the signal corresponding to the pattern length count times the samples per unit interval is acquired beginning at a point in the signal defined by the designated arbitrary data strobe. Thereafter one or more additional portions of the signal are acquired corresponding to the pattern length count times the samples per unit interval at a point in the signal defined by when the number of subsequent data strobes reaches the pattern length count times the samples per unit interval.