Electronic Signals and Logic Gates

Abstract

Digital data consists of sequences of 0 and 1, called binary code. Electronically, One (1) may be represented by the presence of a pulse of certain predefined height in a specified time interval, called the discrete time interval and Zero (0) by the absence of a pulse of that predefined height during the discrete time interval. Alphabets of any language may thus be coded into digital form assigning them different sequences of 0 and 1. Similarly, numbers may also be represented in digital form using different binary-based numeral codes. Analog data may be converted into digital form using analog-to-digital converter (ADC) while the digital data may be obtained back in analog form using digital-to-analog converter (DAC). Logical operations are digitally implemented using Logic Gates. Successive logic operations may be represented by Boolean expressions that follow laws of Boolean algebra. Details of discrete time digital signals, Numeral systems, principle of operation of ADC/ DAC and implementation of Logic gates, rules of Boolean algebra, methods of solving Boolean expressions, etc. are discussed in this chapter. A number of solved examples has been included to illustrate the implementation of Boolean algebra under different circumstances.