Algorithms for Communications Systems and their Applications, 2nd Edition

Chapter 7Single‐carrier modulation

This chapter is split into two parts. The first part considers digital pulse amplitude modulation (PAM) and quadrature amplitude modulation (QAM) for continuous transmission by using a single carrier, taking into account the possibility that the channel may distort the transmitted signal [1–3]. The Nyquist criterion will be given, which states conditions on the pulse at the receiver for the absence of intersymbol interference. The second part instead first presents several equalization methods to compensate for linear distortion introduced by the channel. Then, we analyse detection methods that operate on sequences of samples. Last, we present techniques to estimate the discrete‐time channel impulse response, a starting point of receiver design.

7.1 Signals and systems

With reference to the general scheme of Figure 6.1, here we omit the channel encoder to simplify the analysis, hence, the information message is input to the bit mapper to yield the data sequence

7.1.1 Baseband digital transmission (PAM)

The fundamental blocks of a baseband digital transmission system are illustrated in Figure 7.1, while signals at the various points of a quaternary PAM system are shown in Figure 7.2.

Modulator

For a PAM system, the modulator associates the ...