TIMING EXTRACTION CIRCUIT, COMMUNICATION SYSTEM USING THE CIRCUIT, TIMING EXTRACTION METHOD AND COMMUNICATION EQUIPMENT

摘要

PURPOSE: To provide a timing extraction system which can extract a precise clock when a multilevel transmission code is applied, which can be applied for a great rate transmission that is more than several megabit per second and which fits for LSI of a realized circuit. CONSTITUTION: The timing extraction method is to extract the clock of a baud rate from a multilevel signal which has the prescribed baud rate and generates cross timing with a reference level at frequency timing which is integer number- fold of the baud rate and the method is for obtaining identification data from the multilevel signal in response to the clock. Cross timing between the multilevel signal and a prescribed threshold is detected, and a control signal is generated when a differential signal generated from the multilevel signal is beyond a prescribed threshold area. A baud rate clock synchronized with a data identification point is generated by using the operated result of cross timing and the control signal, and identification data is extracted from the multilevel signal by using the baud rate clock.