US Patent 7248540 Dual channel delay sensing circuit

A circuit coupled to an array antenna, such as a sonar transducer array, for measuring the angle of orientation of an incident wave of radiation is formed of first and second channels coupled to respective portions of the antenna to sense delays between signals of the two channels. A memory retains data of earlier occurring lead and lag measurements. Any subsequent transition from a lead/lag to a lag/lead within a single signal pulse is sensed by a gating circuit which disgards the measurement so as to provide noise immunity.