Today's electronics is completely filled with digital components and we call this "The Digital age". No matter what is the area of application, digital devices have their share. Major part of electronics is now digital. Earlier there were analog computers and they have been removed from the face of earth, once digital computer era started. Slowly one after another all analog electronic machines are converted to digital and thus began the digital revolution.
Though the real world in which we live is analog, why is a digital device dominating? Humans understand an analog signal(we can't interpret binary 1's and 0's as good as analog signals) far better than a digital signal and still they prefer a digital machine to do the job. Why is digital electronics so popular?
In this article I would be addressing all these questions forming a strong base towards why we need digital systems. However there are some places where an analog system works much better than a digital system, I am only trying to make a point that digital systems are a major part of electronics industry today and to survive in such an industry it is compulsory to understand the basics of Digital systems and how to design them.
Q1. What is a Digital VLSI Circuit?
"An electronic circuit that operates on digital inputs to produce the required digital output is called a digital VLSI circuit."
Though the definition seems very simple but there is a lot to understand from it.
- Firstly it is an electronic circuit i.e. the active device behavior is determined by the direction of flow of electrons inside them.
- It operates on digital inputs but not on analog inputs. A digital circuit only understands two voltage levels,one is the supply voltage(logic high normally called VDD) and the second is the ground(logic low,normally called VSS). Any intermediate value is considered an undermined value and the circuit will not work as expected for these values.
- Finally it can only produce digital outputs.
Q2. Why we use digital VLSI circuits?
Though the real world we live is completely analog, digital machines are dominating because of the invaluable benefits they provide. The most important invention of mankind is computer, it changed the world as no one would ever imagine. We are able to do millions of calculations in a fraction of a second, which enables us to do tremendous things like understanding the universe, diagnosing a person for disease, security and lot more. All this is made possible because of computers and more importantly a digital VLSI circuit. So the basic advantages and features of a digital VLSI circuit are,
- Does both numerical and non-numerical information processing very easily.
- Very high noise immunity.
- Easy to design, and the design can be automated(EDA tools and HDLs).
- Low cost(involvement of manpower is low).
- It is very easy to duplicate similar circuits with least performance difference.
Q3. Where do we use digital VLSI circuits?
As said earlier the real world we live is analog and we are talking about digital systems which accepts only digital data as input. For any electronic system the input will come from real world so we need a circuit that can convert the real world analog signals into digital signals and feed them to the digital circuits. Now the digital circuit process the data and returns the result to a circuit which converts the result back to analog. Any electronic device you take this will be the flow.
The following diagram shows the block diagram of any electronic system.
Consider a digital audio system. The input is analog signal(audio from mic) it is then converted to digital and then operated on for noise removal volume,bass and treble are adjusted then converted back to analog signal(speaker).
So what ever is the area of application, digital circuits are used every where. Some examples of application fields are, communication, security,mobiles,space applications,health and treatment,education,defense,etc.
0 comments:
Post a Comment