Symbol lock detection implemented with nonoverlapping integration intervals

A symbol lock detector for an incoming coherent digital communication signal which utilizes a subcarrier modulated with binary symbol data, dk, and known symbol interval T by integrating binary values of the signal over nonoverlapping first and second intervals selected to be T/2, delaying the first integral an interval T/2, and either summing or multiplying the second integral with the first one that preceded it to form a value Xk. That value is then averaged over a number M of symbol intervals to produce a static value Y. A symbol lock decision can then be made when the static value Y exceeds a threshold level delta .