Line Codes A channel has a bandwidth of 3 kHz Assuming that

Line Codes A channel has a bandwidth of 3 kHz. Assuming that we transmit binary digits over this channel, calculate the data rate (in bits per second) that can be supported using: Polar NRZ with rectangular pulses. Bipolar RZ with rectangular pulses.

Solution

Nyquist Criteria for maximum data rate

C = 2 * B * log M

where C is the channel capacity in bits per second, B is the maximum bandwidth allowed by the channel, M is the number of different signalling values or symbols and log is to the base 2.

bandwidth = 3khz=3000

(a) M= 2 and hence maximum channel capacity or achievable data rate is C = 2 * 3000 * log 2 = 6000 bps.

(b) Similarly, if Bipolar is used instead of binary signalling, then M = 4. In that case, the maximum channel capacity is C = 2 * 3000 * log 4 = 2 * 3000 * 2 = 12000bps.