4e4f6560_imator___MATLAB_mfilt_firdecim__Description
[Name] PolyphaseAccum [Values] 0 in double, single, or fixed for the different filter arithmetic settings. [Description] 
Differentiates between the adders in the filter that work in full precision at all times (PolyphaseAccum) and the adders in the filter that the user controls and that may introduce quantization effects when FilterInternals is set to SpecifyPrecision.
Direct-form FIR polyphase decimator - MATLAB mfilt.firdecim