Diversity switch correlation system

A multiple-channel microwave communications system with an improved diversity switch permitting the system to be constructed without the necessity of equalizing channel delays wthin a 1/2 bit period by adjusting coaxial cable lengths. The average clock frequency is made to be the on-line channel frequency. The off-line clock frequency is forced to assume the on-line clock frequency by shifting the off-line clock one-half bit, that is 180 DEG , when it is advanced or delayed more than 180 DEG . Phase shifters of 180 DEG are provided in each channel but with only the off-line channel permitted to shift. In addition, the bit content of the dual channel receiving system is aligned over a plus or minus three-bit range by a correlation loop circuit.