**Bit Rate Vs Baud Rate**

Before examining the types of modulation it may be useful to review the difference between bit rate and baud rate.

Bit rate and baud rate are not always the same. The bit rate is the number of bits transmitted per second, whereas, the baud rate is the number of signal units transmitted per second and one signal unit is able to represent one or more bits. Therefore, baud rate is always less than or equal to the bit rate but never greater.

**Example 1**

What is the bit rate and baud rate for an analogue signal that carries 3 bits in each signal unit if 2000 signal units are sent per second?

Answer:

Baud rate = 2000 baud per second

Bit rate = 2000 x 3 = 6000 bps

**Example 2**

What is the baud rate for an analogue signal if the bit rate of the signal is 2000 and each signal unit carries 4 bits?

Answer:

Baud rate = 2000 / 4 = 500 baud

Next: 3.4 Modulation