Baud rate

The baud rate is the number of signal changes that occur per second.

For example, if we have a baud rate of 9600, that means that there are 9600 signal changes per second (the number of times that the signal changes its state / value per second).

This isn’t always the same as the bit rate, because a single signal change can sometimes represent multiple bits of data, depending on the way we encode the data. For example, if we use a modulation scheme that allows us to encode 4 bits per signal change, then a baud rate of 9600 would correspond to a bit rate of 38400 bits per second (9600 signal changes per second * 4 bits per signal change = 38400 bits per second).

Calculating baud rate

If we know the bit rate and the number of bits per signal change, we can calculate the baud rate using the formula:

\text{Baud rate} = \frac{\text{bit rate}}{\text{Bits per signal change}}

flashcards

Question	Answer
Baud rate definition	The number of signal changes that occur per second.
Example of a 9600 baud rate	There are 9600 signal changes per second.
Is baud rate always the same as bit rate?	No, because a single signal change can sometimes represent multiple bits of data, depending on the encoding scheme.
If a modulation scheme encodes 4 bits per signal change, what bit rate does a 9600 baud rate give?	Bit rate of 38400 bits per second (9600 signal changes/second * 4 bits per signal change).
Formula to calculate baud rate given bit rate and bits per signal change	\text{Baud rate} = \frac{\text{bit rate}}{\text{Bits per signal change}}
How do you calculate bit rate from baud rate?	Multiply baud rate by bits per signal change e.g., 9600 \times 4 = 38400 bits per second.