ABSTRACT
We have seen in the last chapter that time division multiplexing (TDM) technology is responsible for the high number of voice channels that can be multiplexed into a single transmission medium. Although the TDM techniques are not strictly restricted to the digital world, as they can very well be deployed on analog links too, with the help of sampling and applying pulse amplitude modulation, pulse width modulation, and pulse position modulation techniques (PAM, PWM, or PPM, respectively, discussed later in this chapter) are not useful for long-distance links, owing to the accumulation of the impairments described in Chapter 2. Thus, today whenever we talk of TDM, it is with reference to digital TDM.
