# What's the relationship between bandwidth and symbol rate for a modulated signal?

I was hoping somebody could help me with understanding the relationship between the bandwidth of a modulated carrier signal (say using QPSK) and the symbol rate(s) you can transmit across a channel. If anyone knows links to helpful visual representations please link them here. Thanks in advance.

• $\pi /2 ~~ QPSK$ is even better with Trellis and FEC – Tony Stewart EE75 Mar 2 at 21:40