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