  In this paper, we revisit a recently proposed receiver design, named the
splitting receiver, which jointly uses coherent and non-coherent processing for
signal detection. By considering an improved signal model for the splitting
receiver as compared to the original study in the literature, we conduct a
performance analysis on the achievable data rate under Gaussian signaling and
obtain a fundamentally different result on the performance gain of the
splitting receiver over traditional receiver designs that use either coherent
or non-coherent processing alone. Specifically, the original study ignored the
antenna noise and concluded on a 50% gain in achievable data rate in the high
signal-to-noise ratio (SNR) regime. In contrast, we include the antenna noise
in the signal model and show that the splitting receiver improves the
achievable data rate by a constant gap in the high SNR regime. This represents
an important correction of the theoretical understanding on the performance of
the splitting receiver. In addition, we examine the maximum-likelihood
detection and derive a low-complexity detection rule for the splitting receiver
for practical modulation schemes. Our numerical results give further insights
into the conditions under which the splitting receiver achieves significant
gains in terms of either achievable data rate or detection error probability.
