Phase detector for phase locked loop includes calculator calculating input-output products in order to detect phase shift

摘要

The system uses a product derived from input and corresponding output symbols, in order to detect the phase shift. The phase detector is intended for operation in a phase locked loop circuit. It comprises a circuit calculating the products of the type (qm.dm), where qm is the input symbol of the phase detector and dm is the conjugate of the corresponding output symbol (or the conjugate of the decision on this output symbol). The circuit delivers a voltage (wm) which is representative of a phase difference between two products (qm.dm) and (qm-x.dm-x), obtained for two distinct input symbols (qm and qm-x).