Noe R, Rückert U, Hoffmann S, et al. Real-time implementation of digital coherent detection. In: Optical Communication, 2009. ECOC '09. 35th European Conference on. 2009: 1-4.The implementation of algorithms for coherent detection of advanced modulation formats imposes constraints. A hardware-efficient phase estimator is presented, and measurement results with a CMOS receiver chip designed for 40 Gb/s digital coherent polarization-multiplexed QPSK