SIMULATION AND ITS IMPORTANCE IN THE VLSI DESIGN

It is a design validation tool to check circuit’s function and other parameters such as performances. These tools are available for all levels of design. Four types of simulation tools are:
1 CIRCUIT SIMULATION: - It performs a detailed analysis of voltages and currents in the circuit.
2 TIMING SIMULATION: - Simulates large circuits which are not possible by circuit simulations.
3 SWITCH SIMULATION: - Treats the transistors are ideal or semi-ideal switches.
4 GATE SIMULATION: - It uses the logic gate as the fundamental unit of simulation.

Simulation can be done at two levels:
1 Before the layout is complete.
2 After the completion of layout.
It checks hundreds of transistor on a computer but we have thousands of transistors in VLSI chip.

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VLSI Design

VLSI design has become a major driving force in modern technology. It provides the basis for computing and telecommunications, and the field continues to grow at an amazing pace. The field of VLSI design is a resource-intense engineering discipline. Project and product definitions are economically motivated, and competition on a worldwide basis is very keen. The market potential for innovative designs is very large, but the market wise often short due to both competitions and changing consumer demands. The microscopic dimensions of current silicon integrated circuitry make possible the design of digital circuits, which may be very complex and yet extremely economical in space, power requirements and cost, and potentially very fast. The space power and cost aspects have made silicon the dominant fabrication technology for electronics in very wide ranging areas of application. The combination of complexity and speed is finding ready applications for VLSI systems in digital processing and particularly in those application areas requiring sophisticated high speed digital processing.

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4G APPLICATIONS AND THEIR BENEFITS TO PUBLIC SAFETY

One of the most notable advanced applications for 4G systems is location based services. 4G location applications would be based on visualized, virtual navigation schemes that would support a remote database containing graphical representations of streets, buildings, and other physical characteristics of a large metropolitan area. This database could be accessed by a subscriber in a moving vehicle equipped with the appropriate wireless device, which would provide the platform on which would appear a virtual representation of the environment ahead.
For example, one would be able to see the internal layout of a building during an emergency rescue. This type of application is sometimes referred to as "Telegeoprocessing", which is a combination of Geographical Information Systems (GIS) and Global Positioning Systems (GPS) working in concert over a high-capacity wireless mobile system.
Telegeoprocessing over 4G networks will make it possible for the public safety community to have wireless operational functionality and specialized applications for everyday operations, as well as for crisis management.
The emergence of next generation wireless technologies will enhance the effectiveness of the existing methods used by public safety. 3G technologies and beyond could possibly bring the following new features to public safety:


5.1. Virtual navigation:

As described, a remote database contains the graphical representation of streets, buildings, and physical characteristics of a large metropolis. Blocks of this database are transmitted in rapid sequence to a vehicle, where a rendering program permits the occupants to visualize the environment ahead. They may also "virtually" see the internal layout of buildings to plan an emergency rescue, or to plan to engage hostile elements hidden in the building.


5.2. Tele-medicine:

A paramedic assisting a victim of a traffic accident in a remote location could access medical records (e.g., x-rays) and establish a video conference so that a remotely based surgeon could provide “on-scene” assistance. In such a circumstance, the paramedic could relay the victim's vital information (recorded locally) back to the hospital in real time, for review
by the surgeon.


5.3. Crisis-management applications:

These arise, for example, as a result of natural disasters where the entire communications
infrastructure is in disarray. In such circumstances, restoring communications quickly is essential. With wideband wireless mobile communications, both limited and complete communications capabilities, including Internet and video services, could be set up in a matter of hours. In comparison, it may take days or even weeks to re-establish communications capabilities when a wire line network is rendered inoperable.

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4G -Technology

The approaching 4G (fourth generation) mobile communication systems are projected to solve still-remaining problems of 3G (third generation) systems and to provide a wide variety of new services, from high-quality voice to high-definition video to high-data-rate wireless channels. The term 4G is used broadly to include several types of broadband wireless access communication systems, not only cellular telephone systems. One of the terms used to describe 4G is MAGIC—Mobile multimedia, anytime anywhere, Global mobility support, Integrated wireless solution, and Customized personal service. As a promise for the future, 4G systems, that is, cellular broadband wireless access systems have been attracting much interest in the mobile communication arena. The 4G systems not only will support the next generation of mobile service, but also will support the fixed wireless networks.

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MEMS and Nanotechnology Applications

There are numerous possible applications for MEMS and Nanotechnology. As a breakthrough technology, allowing unparalleled synergy between previously unrelated fields such as biology and microelectronics, many new MEMS and Nanotechnology applications will emerge, expanding beyond that which is currently identified or known. Here are a few applications of current interest:
Biotechnology
MEMS and Nanotechnology is enabling new discoveries in science and engineering such as the Polymerase Chain Reaction (PCR) microsystems for DNA amplification and identification, micromachined Scanning Tunneling Microscopes (STMs), biochips for detection of hazardous chemical and biological agents, and microsystems for high-throughput drug screening and selection.
Communications
High frequency circuits will benefit considerably from the advent of the RF-MEMS technology. Electrical components such as inductors and tunable capacitors can be improved significantly compared to their integrated counterparts if they are made using MEMS and Nanotechnology. With the integration of such components, the performance of communication circuits will improve, while the total circuit area, power consumption and cost will be reduced. In addition, the mechanical switch, as developed by several research groups, is a key component with huge potential in various microwave circuits. The demonstrated samples of mechanical switches have quality factors much higher than anything previously available.
Reliability and packaging of RF-MEMS components seem to be the two critical issues that need to be solved before they receive wider acceptance by the market.
Accelerometers
MEMS accelerometers are quickly replacing conventional accelerometers for crash air-bag deployment systems in automobiles. The conventional approach uses several bulky accelerometers made of discrete components mounted in the front of the car with separate electronics near the air bag; this approach costs over $50 per automobile. MEMS and Nanotechnology has made it possible to integrate the accelerometer and electronics onto a single silicon chip at a cost between $5 to $10. These MEMS accelerometers are much smaller, more functional, lighter, more reliable, and are produced for a fraction of the cost of the conventional macroscale accelerometer element

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Advantages of MEMS and Nano Manufacturing

First, MEMS and Nanotechnology are extremely diverse technologies that could significantly affect every category of commercial and military product. MEMS and Nanotechnology are already used for tasks ranging from in-dwelling blood pressure monitoring to active suspension systems for automobiles. The nature of MEMS and Nanotechnology and its diversity of useful applications make it potentially a far more pervasive technology than even integrated circuit microchips.
Second, MEMS and Nanotechnology blurs the distinction between complex mechanical systems and integrated circuit electronics. Historically, sensors and actuators are the most costly and unreliable part of a macroscale sensor-actuator-electronics system. MEMS and Nanotechnology allows these complex electromechanical systems to be manufactured using batch fabrication techniques, decreasing the cost and increasing the reliability of the sensors and actuators to equal those of integrated circuits. Yet, even though the performance of MEMS and Nano devices is expected to be superior to macroscale components and systems, the price is predicted to be much lower.

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Fabricating MEMS and Nanotechnology

MEMS and Nano devices are extremely small—for example, MEMS and Nanotechnology has made possible electrically-driven motors smaller than the diameter of a human hair (right) -- but MEMS and Nanotechnology is not primarily about size.
MEMS and Nanotechnology is also not about making things out of silicon, even though silicon possesses excellent materials properties, which make it an attractive choice for many high-performance mechanical applications; for example, the strength-to-weight ratio for silicon is higher than many other engineering materials, which allow very high-bandwidth mechanical devices to be realized.
Instead, the deep insight of MEMS and Nano is as a new manufacturing technology, a way of making complex electromechanical systems using batch fabrication techniques similar to those used for integrated circuits, and uniting these electromechanical elements together with electronics.

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Next Generation DATA STORAGE on Nanometre-scale

Imagine having all the information recorded on a stack of 1,540 CDs on a disk the size of single CD. Or visualise having all the information recorded on a stack of 154 CDs written on a one inch square chip.
New probe microscopy techniques and new organic materials could be combined in the next generation data storage technology - which will be nanometre scale technology with major - impact on related storage technologies.
We can believe that nanotech organic films will be the storage date medium of the near future, using micro-electro-mechanical systems, or MEMS probe devices, to read and write on the medium. Information will be written, read and stored in clusters of molecules within the inexpensive films. By current conventional, a CD (optical disk drive) holds 500 megabits of data per square inch. And by current conventional

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.) NANOSCROLLS --- alternative to nanotubes

Production of carbon nanoscrolls, an alternative to nanotubes has been a new alternative to nanotubes. ULCA chemists reported a room temperature chemical method for producing a new type of carbon called carbon nanoscolls. Now, what are these Nanoscrolls ? Nanoscrolls are very closely related to much touted nanotubes but have significant advantages over them

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