Regarding polyphase IIR filter.

Dear All,

            Iam working subband acoustic echo cancellation.In that for
subbanding the input signal i used polyphase IIR filter.I searched in
net for polyphase IIr filter design.I got some techinical documents
related to polyphase IIr filter, I mentioned important links related to
documents below.
1 http://users.cscs.wmin.ac.uk/~krukowa/pdf/Paper27.pdf
2http://ieeexplore.ieee.org/iel5/8570/27140/01205861.pdf.

          In this document the filter coeffecients are also mentioned,
But there is no time domain difference equation.I derived the
difference equation from the transfer function given in the document
and implement the filter.But the output of the filter is not clear.Give
me some valluable suggestions on time domain difference equation of
polyphase IIR filter.

                           Thanks in advance.

                                                              venkat.