  Microwave transversal filters, which are implemented based on the transversal
filter structure in digital signal processing, offer a high reconfigurability
for achieving a variety of signal processing functions without changing
hardware. When implemented using microwave photonic (MWP) technologies, also
known as MWP transversal filters, they provide competitive advantages over
their electrical counterparts, such as low loss, large operation bandwidth, and
strong immunity to electromagnetic interference. Recent advances in high
performance optical microcombs provide compact and powerful multiwavelength
sources for MWP transversal filters that require a larger number of wavelength
channels to achieve high performance, allowing for the demonstration of a
diverse range of filter functions with improved performance and new features.
Here, we present a comprehensive performance analysis for microcomb based MWP
spectral filters based on the transversal filter approach. First, we
investigate the theoretical limitations in the filter spectral response induced
by finite tap numbers. Next, we analyze the distortions in the filter spectral
response resulting from experimental error sources. Finally, we assess the
influence of input signals bandwidth on the filtering errors. These results
provide a valuable guide for the design and optimization of microcomb-based MWP
transversal filters for a variety of applications.
