Skew estimator, skew compensator and coherent receiver

摘要

A skew estimator for estimating a skew between a first signal of a first data path and a second signal of a second data path in a coherent receiver is provided. The skew estimator comprises a phase detector and an integrator. The phase detector is configured to detect a phase of the first signal or the second signal to obtain a phase signal. Further, the integrator is configured to integrate the obtained phase signal to provide an estimated skew.

主权项

1. A skew estimator for estimating a skew in a coherent receiver, the skew estimator comprising:
four phase detectors configured to detect a respective phase of an X-polarized in-phase signal (XI), an X-polarized quadrature-phase signal (XQ), a Y-polarized in-phase signal (YI) and a Y-polarized quadrature-phase signal (YQ) to obtain four phase signals; an adder configured to provide a sum signal by adding the obtained four phase signals; four blocks for the obtained four phase signals, wherein each block corresponds to one phase signal out of the obtained four phase signals, and each block comprises:
a subtractor configured to provide a difference signal between the sum signal and a respective phase signal out of the obtained four phase signals,a low-pass filter configured to filter the output difference signal,a determiner configured to determine the sign of the filtered differential signal to obtain a sign signal, andan integrator configured to integrate the obtained sign signal to provide an estimated skew (φXI) of the respective phase signal.