A low-jitter symbol timing recovery scheme for M-QAM systems

A low jitter symbol timing recovery (STR) scheme based on the Costas loop is presented. The equivalence between the introduced Costas STR and the zero-jitter squarer is discussed. The Costas STR scheme, not only eliminates the need of pre-filtering, but also avoids the use of the non-linear function. The Costas STR scheme can achieve an extremely low jitter performance. Applications of the Costas STR into M-ary transmission systems are discussed