Baud rate refers to the number of signal changes (symbols) that occur per second in a communication channel, while bit rate is the number of bits transmitted per second. While they are similar, they are not always the same because a single symbol can represent more than one bit.
The two are equivalent when each symbol represents only one bit, which is commonly the case in simple binary systems. For example, in traditional serial communication using two levels (e.g., mark and space), a baud rate of 9600 would correspond to a bit rate of 9600 bits per second.
However, in more complex modulation schemes, such as Quadrature Amplitude Modulation (QAM), a single symbol can represent multiple bits. For instance, if a baud rate is 2400 but each symbol represents 4 bits, the bit rate would be 9600 bits per second (2400 baud × 4 bits/symbol).
In summary, baud rate and bit rate can be the same in basic binary signaling, but they differ when multiple bits are encoded per symbol in advanced communication techniques.