Clock data recovery circuit and clock data recovery method

• Main Authors: SUNAGA KAZUHISA, YAMAGUCHI KOUICHI
• Format: Patent
• Language: English
• Published: 08.07.2014
• Subjects: ELECTRIC COMMUNICATION TECHNIQUE; ELECTRICITY; TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHICCOMMUNICATION

A clock data recovery circuit includes: a demodulation filter that receives a transmission signal transmitted by two orthogonal carrier waves having I and Q phases and executes demodulation to obtain a demodulated wave having an phase and a demodulated wave having a Q phase from the transmission signal; a first determination circuit that determines whether an absolute value of one of the two demodulated waves is greater than an eye opening maximum value at an ideal clock phase of the transmission signal; a second determination circuit that determines whether the one demodulated wave is greater than zero; a third determination circuit that determines whether the other one of the two demodulated waves is greater than zero; and a phase comparison unit that detects whether a phase of a clock signal included in the transmission signal is leading a phase of a data signal included in the transmission signal, based on determination results obtained by the first to third determination circuits.