Abstract: The present invention is directed to circuitry for achieving an improved carrier synchronization (i.e. estimation of carrier's phase) and data detection for digital data, suppressed carrier transmission systems. A new method--and corresponding apparatus--for pattern jitter cancellation and quadrant ambiguity removal, when incorporated within known or new carrier recovery scheme, results in an improved carrier synchronization and data detection. The resultant carrier recovery and data detection circuitry might be employed for phase estimation and the detection of balanced and unbalanced, coded or uncoded, quadrature amplitude modulation signals. Global positioning system receivers, cable, satellite and radio systems are some examples of where these circuitry might find an application.