Baseband clock recovery algorithm for /spl pi//4-QPSK modulated signals

A new baseband clock recovery algorithm for /spl pi//4-QPSK modulated signals is proposed. Conventionally the clock recovery methods with a non-data-aided algorithm for /spl pi//4-QPSK modulated signals are based on square devices and the jitter performance of those methods is usually worse than that of the clock recovery methods with a data-aided algorithm. However, the data-aided algorithm suffers from slow initial acquisition and is prone to the potential error accumulation. The proposed clock recovery method adopting a new non-data-aided algorithm shows jitter performance close to that of the data-aided ones, as well as removes the error accumulation problem and achieves fast clock recovery.