Interesting, what is the maximum bitrate, anyway?

hi, everybody!!!

The readme file for the benchmark_tx.py under
gnuradio-examples/python/digital indicates to us some machine will do
1Mbps or more, which means in my opinion, the maximum bitrate for USRP
is around 1Mbps. But according to “bitrate = converter_rate / interp /
samples_per_symbol*bit_per_symbol” in the pick_bitrate.py, I found that
the maximum bitrate is up to 4Mbps. Why did the author imply that the
maximum is around 1Mbps? What does he mean, “some machine” will do
1Mbps? Bitrate depends on my computer? But the speed of my CPU is upto
3GHz! Anyone could explain this for me? I am confused…

Tianning