Signal/noise ratio in pulse code modulation

Formulae are derived for the output signal/noise ratio in simple pulse code modulation systems for all values of input signal/noise ratios. The output ratio improves very rapidly with increasing input ratio provided the latter exceeds a certain critical value. It is shown that the system is useful for links connected in tandem, for the degradation of performance below a single link may be avoided by a relatively small increase of power in each link.