Time reversed processing for maximum phase filter in 8PSK

Hi

I'm trying to compare performance with and without minimum phase
prefilter
for 8PSK equaliser with a DDFSE. When we employ a prefilter, we use
min
phase all pass prefilter for 2nd half and max phase all pass
prefilter for
1st half. Hmin_ap , Hmax_ap would be these all-pass filters for
filtering
data, and Hmin and Hmax would be channel estimates to give to DFSE,
corresponding to this data. Hmax would be time reversed complex
conjugate
of Hmin. DFSE works in reverse direction for Hmax (1st half burst)
My question is towards modelling for "no prefilter scenario". When we
dont
want any prefilter but want to use same DFSE (working in fwd, rev
directions as above), minimum phase works fine with slight
degradation, as
expected. Estimated channel is as such treated as Hmin, and no
filtering is
applied on min data. For maximum phase part, no filtering of data is
applied, and Hmax is identified as conj(Hmin(n:-1:1)). But this
maximum
phase part gives significant errors compared to minimum phase, which
is
totally unexpected (even at high SNR).
Please clarify whether I'm missing any scaling or other operations
that
may be required specific to "maximum phase prefiltering with time
reversed
processing".
Thanks in advance
Sundar Rajan Start a New Thread