We have recently extended the concepts of generalized channeled polarimetry to keep proper account of all the multi-carrier harmonics generated by Photoelastic Modulators (PEMs). In order to build a Mueller matrix polarimeter out of such devices, the system needs to include at least four PEMs, each modulating at a different frequency. In our previous treatment, we have deliberately deferred the concept of multi-carrier harmonics of different PEMs mixing within the same channel. Despite the choice being a reasonable one due to the difficulty of precisely controlling PEMs' mechanical resonance properties due to manufacturing tolerances and temperature dependence, there are instances where having mixed channels enables a significantly better reconstruction SNR. Here, we revisit the omission by quantifying the additional performance that can be achieved with mixed channels, and explore the bounds on the level of frequency shift control required to ensure the predicted performance. We demonstrate that deliberate design of mixed channels is particularly beneficial when reconstructing with a low number of channels. Conversely, the level of control required to ensure an accurate enough alignment of higher harmonics leads to diminishing returns when reconstructing with a high number of channels.
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