Method and apparatus for time aligning data modulators using frequency domain analysis of detected output

摘要

Method and apparatus for time aligning first and second signals. The second signal is modulated by the first signal to provide a third signal. Frequency components of the third signal are then determined, the frequency components being indicative of time alignment between the first and second signals. The method and apparatus is particularly suitable for converting a Non-Return-to-Zero data signal to a Return-to-Zero data signal by modulating the Non-Return-to-Zero data signal with a Return-to-Zero pulse signal. The method and apparatus provides for the Non-Return-to-Zero data signal and the Return-to-Zero pulse signal being correctly time aligned in an automated manner without human intervention.