Smart Cards and Communicaiton

A Smart Card or Integrated Circuit Card (ICC) is very small as any pocket-sized card with embedded integrated circuits which can process data. It can receive input which is processed by way of the Integrated Circuit Card applications and delivered as an output.

This Integrated Circuit may consist only of EEPROM in the case of a memory card, or it may also contain ROM, RAM and even a CPU.

Smart Cards have been designed with the look of a credit or debit card, but can function on at least three levels, credit - debit - personal information. Smart Cards include a microchip as the central processing unit, random access memory (RAM) and data storage of around 10MB.

Smart Card is a mini-computer without the display screen and keyboard. Smart cards contain an operating system just like personal computers. Smart cards can store and process information and are fully interactive. Advanced smart cards also contain a file structure with secret keys and encryption algorithms. Due to the encrypted file system, data can be stored in separated files with full security.

Smart cards typically hold 2,000 to 8,000 electronic bytes of data. Due to those bytes can be electronically coded; the effective storage capacity of each card is significantly increased. Magnetic stripe cards, such as those issued by banks and credit card companies, lack the security of microchips but remain inexpensive due to their status as a single purpose card. Smart cards can be a carrier of multiple records for multiple purposes. The distributed processing possible with smart cards reduces the need for ever-larger mainframe computers and the expense of local and long-distance phone circuits required to maintain an on-line connection to a central computer.

Smart Card Usage

Computer security: - The Mozilla Firefox web browser can use smart cards to store certificates for use in secure web browsing.

Some disk encryption systems, such as FreeOTFE (On The Fly Encryption), can use Smart Cards to securely hold encryption keys.

Smart Cards are also used for single sign-on to log on to computers

Financial: - Smart Cards include their use as credit or ATM cards, in a fuel card, SIMs for mobile phones, authorization cards for pay television, pre-pay utilities in household, high-security identification and access-control cards, and public transport and public phone payment cards.

Identification: - A quickly growing application is in digital identification cards. In this application, the cards are used for authentication of identity. The smart card will store an encrypted digital certificate issued from the PKI (public key infrastructure) along with any other relevant or needed information about the card holder.

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How to make right selection between FPGA and DSP

FPGA is an electronic device that helps the design engineers to create custom logic for high commutation signal processing and DSP is a CPU for signal processing applications that has been designed to execute signal processing algorithms for which the principle algorithm that is multiply-and-accumulate operation is similar to all other algorithms. In the implementation of DSP (Digital Signal Processor) and FPGA (Field Programmable Gate Array), design engineers focus on various parameters such as: Power Consumption, System Performance, Form Factor, System’s Future Upgrade Ability, Non-Recurring Engineering (NRE) Investment, Bill-of-Materials (BOM) Cost and Project Risk. Generally the engineers know about DSP but not completely aware of FPGA and hence this creates a situation where they need to select any one of them.

These devices are very different from each other and designed to serve different purposes. DSP provide an optimized platform for signal processing algorithms implemented in software whereas FPGA were for glue logic. Nowadays, there are certain applications where both these devices deliver optimum solutions. FPGA is the better choice for networking applications and DSP is at its best in video applications. This example indicates their performance has gone through a remarkable change over the years.

In terms of cost-performance values, DSP and FPGA are compared in three MMAC (Millions of Multiply-Accumulate Operations per Second) performance categories viz. High, Medium and Low.

MMAC is the number of fixed-point-32-bit or single-precision floating-point multiply-and-accumulate operations that can be executed in units of millions per second. The table given below can help the design engineers in making the right selection between DSP and FPGA.

MMAC Category	Device Cost Range	Minimum Cents/MMAC for FPGA	Minimum Cents/MMAC for DSP
High (>1000 MMAC)	$100 to $300	2.9	5.8
	$300 to $1000	4.2	13.4
	$1000 to $10000	20	-
Medium (300 to 1000 MMAC)	$10 to $30	1.4	1.6
	$30 to $100	2.8	3
Low (<300>	< $10	-	1.8

For applications with perfor­mance requirements above 1000 MMAC, FPGA/DSP Hybrid solu­tions are often the ideal solution. These applications often include multiple signal processing algo­rithms, some of which have low performance requirements. In such cases, relatively inexpen­sive DSPs can implement the algorithms with low-to-medium performance requirements, leaving the higher-performance algorithms to FPGAs. For designs with MMAC re­quirement below 300 MMAC, DSPs are in general the optimum solution from cost/performance perspective. For designs with MMAC requirement between 300 and 1000 MMAC, the DSP is generally preferable when it comes with application specific resources (such as video/audio ports, ARM processor, etc., as is the case with the DaVinci digi­tal media processors). When a DSP with application specific resources does not exist, other aspects of the design must be considered.

Applications where system architects search for platforms provided by DSP and FPGA such as video ports and other interface connectivity, digital signal processing power, for executing management and controlling tasks are:

• Digital Cameras

• Digital Video Recorders

• Set-top-boxes in video applications

• Entertainment devices
  

Touch Screen Monitors: Developments

Touch screen monitors are a device by which we give inputs and take outputs as information without using any other external device. Instead of using a keyboard or mouse.

A touch screen is a display which can detect the presence and location of a touch within the display area. The term generally refers to touch or contact to the display of the device by a finger or hand. Touch screens can also sense other passive objects, such as a stylus.

The touch screen has two main qualities. First, it allows you to interact with what is displayed directly on the screen, where it is displayed, rather than indirectly with a mouse (computing) or touchpad. Secondly, it lets one do so without requiring any intermediate device, again, such as a stylus that needs to be held in the hand.

Touch screen monitors are used in a variety of different applications including POS (point of sale) cash registers, PDA's (personal digital assistants), ATM's, car navigation screens, cell phones, gaming consoles and any other type of appliance that requires you to input and receive information.

Types of technology available in Touch Screen. The commonly used are underneath:

• Resistive Touch monitors

A resistive touch screen monitor usually has a coat of very thin electrically conductive and resistive layer of metal. When pressed, the change in electrical current can be measured and the input processed by a computer. While very affordable they only offer about 75% clarity, they can also be easily damaged by objects that are sharp. Resistive touch screen monitors are the most popular types of touch screen monitors used today. They are usually not effected by dust or liquids which make them very reliable.

• Surface Wave Touch Screen Monitors

Surface wave touch screen monitors use ultrasonic waves to process inputs from the screen. Ultrasonic waves flow over the touch screen, when a person touches the pad at a specific location, the wave is absorbed and immediately processed by the computer. While not as common as resistive touch panels, they are used in certain applications. Dust and water can contaminate a surface wave touch screen so it is important to keep the screens properly maintained.

• Capacitive Touch Screen Monitors

Capacitive touch screens are coated with indium tin oxide. This material provides a continuous current across the screen. The current is precisely controlled throughout the touch pad and can be measured by the computer processor, when touched; the screen is able to send the processor specific coordinates to input information correctly. It is important to note that specific objects can only be used on capacitive touch screens. You can not use a stylus or a pencil for instance; usually you will need a bare finger. Capacitive touch screens have high clarity and are not affected by dust or liquids.

• Infrared Touch Screen Monitors

There are two types of Infrared touch screen monitor screens, the first reacts to infrared or thermal waves (heat), unfortunately this technology is slow and does not work well with cold hands or objects. The second type of Infrared touch screen monitors use vertical and horizontal infrared sensors around the perimeter of the touch screen. Creating a grid, the touch screen is able to pinpoint the exact location of where the screen has been touched and send that information to the computer for processing. Infrared touch screen monitors are very durable and are used for industrial and military applications.
There are many different types of touch screen technology available. The most common types include: Resistive, Surface Wave, Capacitive and Infrared.

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Communications Satellite

A communications satellite (sometimes abbreviated to Comsat) is an artificial satellite stationed in outer space for the purposes of telecommunications. Modern communications satellites use a variety of orbits including geostationary orbits, other elliptical orbits and low (polar and non-polar) Earth orbits. For fixed services, communications satellites provide a microwave radio relay technology complementary to that of fiber submarine communications cables. They are also used for mobile applications such as communications to ships, vehicles, planes and hand-held terminals, and for TV and radio broadcasting, for which application of other technologies, such as cable, is impractical or impossible.
The main problem with microwave communications is that the curvature of earth, mountains and other structures often block the line-of-sight. Due to these reason, several repeater stations are normally required for long distance transmission which increases the cost of data transmission between two points. This problem is removed by using communications satellite which are relatively newer and more promising data transmission media.
A communications satellite is basically a microwave radio relay placed in outer space. These satellites are launched either by rockets or by space shuttles and are precisely positioned 36000 kms above the equator with an orbit speed that exactly matches the earth’s rotation speed. Since a satellite is positioned in geosynchronous orbit, it is stationary corresponding to earth and always stays over the same point on ground. This allows ground station to aim its antenna at a fixed point in the sky. Dozens of satellite are now in orbit to handle international and domestic data, voice and video communication needs. The Indian satellite, INSAT-1B is positioned in such a way that it is accessible from any place of India. The main advantage of communications satellite is that it is single microwave relay station visible from any point of a very long distance. For example, satellite used for national transmission is visible from any part of the country. Thus transmission and reception can be between any two randomly chosen places in that area. Moreover, transmission and reception costs are not dependent upon distances between two points. In addition to this, a transmitting station can receive back its own transmission and check weather the satellite has transmitted the information correctly or not. If an error is detected, the data would be retransmitted. Hence necessary security measures are to be taken to prevent unauthorized tampering of information.The nature of future communications satellite systems will depend on the demands of the marketplace (direct home distribution of entertainment, data transfers between businesses, telephone traffic, cellular telephone traffic, etc.); the costs of manufacturing, launching, and operating various satellite configurations; and the costs and capabilities of competing systems - especially fiber optic cables, which can carry a huge number of telephone conversations or television channels. In any case, however, several approaches are now being tested by satellite system designers.

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V-SATs

V-SATs are used to access those satellites which revolve in the geosynchronous orbit to move the data from one terminal to other terminals. These terminals are the earths stations which are interconnected in mesh configuration but the master earth stations called as Hub are connected in star topology. V-SAT is a very small aperture terminal, a two-way satellite ground station having a size of less than 3 meters with a dish antenna. The size of V-SAT antenna varies from 75cm to 1.2m.

High powered components and antennas are used in the V-SAT technology. In addition to a receiver, V-SAT also has a transmitter that sent the signal back to the originating satellite for which each transponder provides a return path with a separate frequency shared by other terminals using a TDMA technology.

V-SATs operating in star topology transport data via satellite to each V-SAT terminal through Network Operating Centers where as those working in mesh topology, transfers data to each terminal by acting as a hub rather using any such centers.

V-SATs operate in three frequency band which are Band – C, Band – Ku & Band – Ka. Lets consider each one by one.

• Band C: It has a frequency of 3 to 7 GHz having large footprint area, deliver low power with minimum rainfall effect.
• Band Ku: This band has medium foot-print area and power with moderate rainfall effect operating in the range of 10 to 18 GHz.
• Band Ka: It has the highest range of frequency i.e. 18 to 31 GHz and power delivery but the footprint is small and the rainfall effect is also severe.

As we said earlier that V-SAT at each customer location has a transmitter which sends the signal back to its originating satellite. This returned path is transmitted in the L-Band to a low noise block converter device. Hence signal is converted into higher satellite transmission frequency, amplified and finally emitted to the dish antenna that covers the entire satellite with its beam avoiding the uplink frequencies used by its adjacent satellites to prevent the interference.

V-SATs are easily deployed in few minutes. Due to its wireless connectivity to all the stations, it is very helpful in disaster or back up recovery services. With the V-SATs, customer gets a high quality internet performance with the same speed at every location. V-SATs using broadband technology enable to deliver the same data to thousand of location simultaneously without any additional cost.

Nowadays, V-SATs systems are available online in Ka-Band that provides higher bandwidth rates for lower cost. V-SATs are applied for different applications due to the introduction of FSS (Fixed Service Satellite) some of which are listed below:

• Video Conferencing
• Phone Conversation
• Internet Fax
• TV Broadcast
• High Speed Communication
• Satellite News Gathering
  

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