VTU eNotes On Logic Design (Computer Science)
About this eBook
Introduction Today, life is with electronics. Electronics has penetrated every aspect of everyone s life. Electronic circuits and systems are divided into two broad categories based on the type of signals they process
Analog Electronic Circuits Digital Electronic Circuits
basically Logic design is the design of logic circuits which are basically digital electronic circuits. Electrical, electronics and computer engineers need to have a thorough understanding of logic circuits. These circuits are used to build digital computers, digital calculators, mobile phones, communication systems, and modern household appliances like Television, music systems, DVD players, etc.
Analog Electronic Circuits Analog electronic circuits are designed for use with small signals. It exhibits linear operation. Example Voltage amplifier
The output voltage is the faithful amplified version of the input voltage signal.
Digital Electronic Circuits Digital electronic circuits are used with large signals. It exhibits non-linear operation. Example Remote control circuit for automatic switching of a light Page 1
10CS 33 LOGIC DESIGN
UNIT 1 Digital Principles, Digital Logic
The signal is the current from a light-sensing circuit. The output signal is just ON or OFF and it is not an amplified version of the input signal.
Analog Signal It is continuous and all possible values are represented Continuous-time signal . Virtually all naturally occurring physical phenomena are analog signals. Temperature, Pressure, Velocity, and Speech Sound are signals that take on all possible values between given limits
Example Consider the temperature of water that is heated, which is continuously recorded. It changes smoothly from 23oC room temp. to 80oC as shown below
Discrete-Time Signal Discrete-time signal is defined at discrete times. It may arise by sampling a continuous-time signal, or can be generated directly by some discrete-time process. Example Consider that water temperature is measured and recorded only once every minute.