Tracking Performance of Unbalanced QPSK Demodulators: Part II-Biphase Costas Loop with Active Arm Filters

A previous Costas loop study by the author demonstrated that for biphase modulation considerable improvement in tracking performance could be obtained by employing active arm filters of the integrate-and-dump type as opposed to passive arm filters. The purpose of this part, then, is to demonstrate that a similar performance improvement can be obtained for an unbalanced QPSK modulation.