Figure 1 Down sampled signal
As you can see in Figure 1. There are 5 spots
with severe ISI, while others are good.
Figure 2 Packet with severe ISI
Figure 2 shows the zoom in of Figure 1. How can
one packet gets so much ISI while others are good?
If my RRC filters have any error, all of the packets
should suffer the same problem, right?
Or could it be that the parameters still need
some tweaking? I'm guessing, in an ideal channel(in
simulation), I can use an decimating FIR filter to
replace the polyphase clock sync, while in
experiment, I must use the polyphase clock sync as
well as some kind of equalizer and tweak the
parameters until I lower the ISI below an acceptable
level.
Regards,
Edwin