Shanon’s Criteria – Maximum Data Rate of a Noisy Channel

We have already known that the data rate is limited even in case of the noiseless channel. Random noise is always present in a channel. The channel may again be characterized by the ratio of the signal power to noise power that is known as the Signal-to-Noise Ratio (SNR). It is represented as :

SNR= 10log10(S/N)dB

Shanon derived that in case of a noisy channel the signal can be reconstructed from its discrete form if the data rate is below the maximum data rate.
Maximum data rate= Hlog2(1+S/N) bits/sec
Where H = Bandwidth of the channel and S/N = Signal-to-Noise Ratio