  Microwave photonic (MWP) transversal signal processors offer a compelling
solution for realizing versatile high-speed information processing by combining
the advantages of reconfigurable electrical digital signal processing and
high-bandwidth photonic processing. With the capability of generating a number
of discrete wavelengths from micro-scale resonators, optical microcombs are
powerful multi-wavelength sources for implementing MWP transversal signal
processors with significantly reduced size, power consumption, and complexity.
By using microcomb-based MWP transversal signal processors, a diverse range of
signal processing functions have been demonstrated recently. In this paper, we
provide a detailed analysis for the processing inaccuracy that is induced by
the imperfect response of experimental components. First, we investigate the
errors arising from different sources including imperfections in the
microcombs, the chirp of electro-optic modulators, chromatic dispersion of the
dispersive module, shaping errors of the optical spectral shapers, and noise of
the photodetector. Next, we provide a global picture quantifying the impact of
different error sources on the overall system performance. Finally, we
introduce feedback control to compensate the errors caused by experimental
imperfections and achieve significantly improved accuracy. These results
provide a guide for optimizing the accuracy of microcomb-based MWP transversal
signal processors.
