Patent ID: 7561806

Claim:
A method for making timing alignment for a data transmission system, the method comprising: providing a reference clock signal with a first frequency to a first multiplexer through a phase shifter; providing the reference clock signal to a second multiplexer; generating a first multiplexed signal with a second frequency by the first multiplexer, wherein a second frequency follows the first frequency and is higher than the first frequency by a predetermined proportion; generating a second multiplexed signal by the second multiplexer based on the referenced clock signal and according to the predetermined proportion; sending the first multiplexed signal to a first modulator, wherein the first multiplexed signal is a data signal and the first modulator is a data signal modulator; sending the second multiplexed signal to a second modulator, wherein the second multiplexed signal is a data signal and the second modulator is a data signal modulator; and phase shifting the reference clock signal by the phase shifter before the reference clock signal is provided to the first multiplexer, wherein a timing of the first multiplexed signal at the second frequency can be adjusted by adjusting a timing of the reference clock signal at the first frequency.