Noise (example)
Assuming that a PSTN has a bandwidth (B) of 3000 Hz and a typical signal-to-noise ratio (SNR) of 20 dB, determine the maximum theoretical transmission rate (C) that can be achieved. (S and N is the power (in watts) in the signal and noise respectively)
SNR = 10 log10(S / N) dB (signal-to-noise ratio)
20 = 10 log10(S / N) and (S / N) = 100
C = B log2(1 + (S / N)) bps (Shannon-Hartley Law)
C = 3000 x log2(1 + 100) bps = 19963 bps