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Figure 35-14 A train of pulses each of one second
In the signal of Figure 35-14, how many changes in the signal per second are there?
Three changes per second. Therefore the baud rate is three (3Bd).

There are two voltage levels in 35-14. Each level could represent a ‘1’ or a ‘0’. Since
we are transmitting 3 information bits every second the bit rate is also 3bps.

A B

Figure 35-15 The difference between bps and baud

Figure 35-15(A) we are transmitting two bits, a “1” and a “0”. Every second we transmit one pulse
so the baud rate is 1Bd. Every second we transmit one bit (either a 1 or a 0) so the bit rate is
1bps.

Figure 35-15(B) we now have four different voltage levels represent 00, 01, 10 and 11. How many
signal level changes are there per second? There is one change per second, so the Baud Rate is
1Bd. However since we are now transmitting two bits per second the bit rate is now 2bps. Each
signal pulse represents two bits.

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