After we learned a lot of

SNR-Pe graph(Eb/No to error probability graph)

for different signaling scheme

the book summarize that

"One can compare them[different signaling scheme]

on the basis of SNR required to achieve a specified

probability of error. However, such a comparison would

**not be very meaningful**, unless it were made on

the basis of some constraint, such as a fixed data rate

of transmission or, equivalently, on the basis of a fixed

bandwidth."

since we didn't talked about such constraints when we introduced

the SNR-Pe graph, are they making such assumption?

if not, how can we make use of it?

besides,

how can we equate data rate and bandwidth?

it make sense, but I don't feel very solid about it.