Elements of Digital Communication

The need to send a message over long distances has become the basis for the development of electronic communication systems. The signal is the basic representation of that message, which has identifiable characteristics. With the advancement of electronic technology, the electrical signal has become the most suitable for the transmission of messages. But in its electrical representation, the message cannot be transmitted effectively due to its low frequency and power properties. This chapter will explore the characteristics of a signal when transported by an electronic communication system. Specifically, the phenomena involved with the transmission of a baseband message using the carrier as a pilot signal are presented. This means that the characteristics of the message are not altered at the time of transmission. Thus, the aim is to show the difficulties involved in sending a message without any process, giving rise to the need for modulation of the message in its transmission. The present work presents the advantages of using modulation using a train of pulses as a carrier signal, with its respective restrictions in bandwidth, frequency, and noise.