Bandwidth is defined as the portion of the electromagnetic spectrum occupied by a signal We may also define the bandwidth as the frequency range over which as information signal is transmitted. Bandwidth is the difference between the upper and lower frequency limits of the signal. We already know different types of baseband signals such as voice signal, music signal, t.v signal etc. Each of these signals will have it’s own frequency range. This frequency range of a signal is knows as it’s bandwidth. For example the range of music signal is 20 HZ to 15 KHZ. Therefore the bandwidth is(f2-f1) BW= f2 - f1= 15000-20=14980Hz