## BER performance for M-ary signalling |
Example 3.2 | Question 3.5

#### We would expect intuitively that as we increase the number of symbol states, the ability of the receiver to distinguish between symbols in the presence of noise will decrease, unless we significantly increase the energy in each symbol. Based on exactly the same type of analysis used for the binary case, it can be shown (see Proakis (1989)) that

#### the symbol error probability for M-ary bipolar baseband signalling is given by: #### Ps M-aryBipolar = [(M-1)/M]·erfc([3/(M2-1)]·Es average/N0)1/2 #### where M is the number of symbols used. |

#### This result is plotted here as a function of the average energy per bit Eb rather than the average energy per symbol Es where Eb = Es/k (k is the number of bits per symbol).