#### Question 2.3 Question 2.4

####

## Symbol rate (baud rate)

#### The information transfer rate must not be confused with the rate at which symbols are varied to convey the binary information over the channel. We already know that we can encode several bits in each symbol.

#### The correct definition of symbol rate (sometimes called baud rate) is the rate at which the signal state changes when observed in the communications channel and is not necessarily equal to the information transfer rate. #### Units of Symbol rate --> symbols/second (baud)

#### For example, if a system uses four frequencies to convey pairs of bits through a channel, and the frequency (symbol) is changed every 0.5 ms, then: #### Symbol rate = 1 / 0.5 = 2000 symbols/second (2000 baud) #### The information transfer rate for this example, however, is 4000 bps, as each symbol conveys two bits.