How to perform convolution using polyphase structure
I am not quite sure, if i understand you question properly, it would be better if you ask with detail and maybe with a figure, nevertheless if you want convolution of co-efficents of the transfer function then below might be of help. :



and with regard to splitting.. you can easily do it with something like this :

x(1:2:end) = cos(2*pi*f*t(1:2:end));
x(2:2:end) = cos(2*pi*f*t(2:2:end));