  This work proposes a novel adaptive background compensation scheme for
frequency interleaved digital-to-analog converters (FI-DACs). The technique is
applicable to high speed digital transceivers such as those used in coherent
optical communications. Although compensation of FI-DACs has been discussed
before in the technical literature, adaptive background techniques have not yet
been reported. The importance of the latter lies in their capability to
automatically compensate errors caused by process, voltage, and temperature
variations in the echnology (e.g., CMOS, SiGe, etc.) implementations of the
data converters, and therefore ensure high manufacturing yield. The key
ingredients of the proposed technique are a multiple-input multiple-output
(MIMO) equalizer and the backpropagation algorithm used to adapt the
coefficients of the aforementioned equalizer. Simulations show that the
impairments of the analog signal path are accurately compensated and their
effect is essentially eliminated, resulting in a high performance transmitter
system.
