The Future of Telecommunications

It is impossible today to imagine our world without telecommunications. It's a common sight now to see people walking down the street talking into a mobile phone or hands-free headset. But what we have today is just an intermediate step. In modern laboratories, there are some developments that introduce more sophisticated devices. For example, something you can put in your shirt that will pick up your voice so that you don't need earphones or a microphone. These electronic devices will probably be of nano variety, which means they will be assembled at the molecular or even atomic level, but they will operate like microphones and earphones in today's mobile devices. In fact, you could have full-time connectivity through your shirt or your wallet. Some people will have a strong reaction against this. They will refuse to be connected this way because they will see it as a kind of dependence. But other people, like some smart people in, say, the City of London will be very happy to have a dress that is both beautiful and that can also connect them to whomever they want to stay in touch with.

Nanotechnology will have a tremendous impact because it facilitates full flexibility of use. When you look at the history of communications, it is the development of many different devices. First there was a telephone in a fixed position, then television, then mobile phone, then the Internet, and so on. Delivering these services to the customer was complex, and the customer had to be more or less of an engineer to manage them all. For people who are not technically inclined, it can become a kind of nightmare. So the dream is that all the points of access will be merged into a pocket-size device or even a nano-chip in your clothing, and with that, you can hear music, you can call up a movie on the TV screen, you can play games – you can do whatever you want.

Even more impressive is what will happen in your house. You will have a screen on the wall that will be like a TV screen but won't be dedicated to a single use, like television. Its applications will be flexible and you will have a small device that will let you select how you use it. When you are working, you can use it for computing or the Internet. When you are relaxing, you can watch TV or a movie or some other form of entertainment. Or you can be in touch with your friends. Your TV set can be connected to the Internet now, but it's a secondary usage. The new screen will be neutral and you will manage the way you use it with a device that fits in your pocket.

Telecommunications will also have a considerable influence on businesses and industry. No one can run a company now without being on the Internet. A lot of small businesses that used to only sell locally are now selling internationally, thanks to telecommunications. In fact, there are some start-up businesses that begin on the international level, and once they are established there, they begin selling locally. In the global digital village, your market can come from anywhere. This represents a massive shift in the world economy, and it is going to continue evolving as new technologies are introduced. The revenues in telecommunications drive to the highest of all businesses. Companies will need to keep adjusting to accommodate these changes and the ones that do this best are the ones that will succeed. Flexibility and innovation will be key.

Signal Processing

The intentional operation on a signal produced by one process, an “input signal”, to produce a new signal, an “output signal”, is generally referred to as signal processing. It is an area of electrical engineering and applied mathematics that deals not only with operations on, but also analysis of signals, in either discrete or continuous time, to perform useful operations on those signals. Signals of interest can include sound, images, time-varying measurement values and sensor data, for example biological data such as electrocardiograms, control system signals, telecommunication transmission signals such as radio signals, and many others.

The analysis of signals and the automation of repetitive tasks of recognition are ubiquitous in several applications such as bioengineering, biometrics, industrial inspection, agroindustry, artificial vision, bioacoustics and seismology. Professionals in those areas need advanced data and signal analysis techniques to understand better the nature of their objects of study and the interactions between the variables involved in their corresponding processes. In addition, pattern recognition techniques are able to provide them with advanced and reliable methods to automate classification or identification procedures as well as to assist them in complex decisions such as diagnoses and forecasts.

The topic can be easily illustrated by examples.

· A time-varying voltage waveform is produced by a human speaking into a microphone or telephone. This signal might be modulated for transmission, then it might be digitized and coded for transmission on a digital link. Noise in the digital link can cause errors in reconstructed bits, the bits can be used to reconstruct the original signal within some fidelity. All of these operations on signals can be considered as signal processing, although the name is most commonly used for manmade operations such as modulation, digitization, and coding, rather thatn the natural possibly unaviodable changes such as the addition of thermal noise or other changes out of control.

· For digital speech communications at very low bit rates, speech is sometimes converted into a model consisting of a simple linear filter and an input process. The idea is that the parameters describing the model can be communicated with fewer bits than can the original signal, but the receiver can synthesize the human voice at the other end using the model so that it sounds very much like the original signal. A system of this typr is called a vocoder.

· Signals including image data transmitted from remote spacecraft are virtually buried in noise added to them on route and in the front end amplifiers of the receivers used to retrieve the signals. By suitably preparing the signals prior to transmission, by suitable filtering of the received signal plus niose, and by suitable decision or estimation rukes, high quality images are transmitted through this very poor channel.

· Signals produced by biomedical measuring devices can display specific behavior when a patient suddenly changes for the worse. Signal processing systems can look for these changes and warn medical personnel when suspicious behavior occurs.

· Images produced by laser cameras inside elderly North Atlantic pipelines can be automatically analyzed to locate possible anomalies indicating corrosion by looking for locally distinct random behavior.

How Modems Work

The purpose of a modulator is to modulate (vary) the carrier properties, while a demodulator detects the modulation on the carrier wave and recovers the original waveform at the destination.

Today we don't have all-digital or all-analog networks; we have a mix of the two. Therefore, at various points in a network, it is necessary to convert between the two signal types. To infuse digital data onto transmission facilities and vice versa a two-way computer conversation, the MOdulator and DEModulator are combined into a single device called a 'modem'.

To understand better how modems work, think of how you use the telephone. You don't just pick up the receiver and start talking. You have to go through a series of quite orderly steps: you have to lift the receiver, wait for the dialing tone, dial each number so it's recognized, wait for the sound of the ringing at the other end, listen for the other person's voice, say hello, and then alternate your speech with theirs. If there's no answer, you have to know when to replace the receiver and hang up the call.

Modems have to behave exactly the same way, exchanging information in a very 'orderly' conversation. If you've used a dialup modem, you'll have noticed that your modem opens the line, dials the number, waits for the other modem to reply, and ''handshakes'', before any real data can be sent or received. If there's no reply, it'll hang up the line and tell you there's a problem. ''Handshaking'' is the initial part of the conversation where two modems agree the speed at which they will talk to one another. If you have a very fast modem but your ISP has only a slow one, the two devices will be forced to communicate at the slower speed.

Every dialup modem works according to a particular international standard (a number prefaced by a capital letter V)—and this tells you how quickly it sends and receives data in bits (binary digits) per second (usually abbreviated bps). The older standards, such as V.22 (1200 bps), assumed the connection between two computers was mostly analog; newer standards like V.90 (56,000 bps) achieve higher speeds by assuming the connection is at least partly digital.

When sending information, the modulation process involves the conversion of the digital computer signals (high and low, or logic 1 and 0 states) to analog audio-frequency tones. Digital highs are converted to a tone having a certain constant pitch; digital lows are converted to a tone having a different constant pitch. These states alternate so rapidly that, if you listen to the output of a computer modem, it sounds like a hiss, a screech, or roar. At the other end of your modem connection, the computer attached to its modem reverses this process. The receiving modem demodulates the various tones into digital signals and sends them to the receiving computer. Actually, the process is a bit more complicated than sending and receiving signals in one direction and then another. Modems simultaneously send and receive signals in small chunks. The modems can tell incoming from outgoing data signals by the type of standard tones they use.

Depending upon how your computer is configured and your preferences, you can choose between several modem types.

External modems have their own power supply and connect with a cable to a computer's serial port. The advantages of external modems are that they do not drain any power from the computer, you can turn off the modem to break an online connection quickly without powering down the computer and you can monitor your modem's connection activity by watching the status lights.

Internal modems, usually installed in the computer you buy, are activated when you run a communication programme and are turned off when you exit the programme, which is especially useful for novice users. The major disadvantage with internal modems is their location: when you want to replace an internal modem, you have to go inside the computer case to make the switch.

PC Card modems, designed for portable computers and fit into the PC card slot on notebook and handheld computers. Except for their size, PC Card modems are like a combination of external and internal modems. The cards are powered by the computer, which is fine unless the computer is battery-operated: running a PC Card modem drastically decreases the life of your batteries.

Wireless modems transmit the data signals through the air instead of by using a cable. They sometimes are called a radiofrequency modem. This type of modem is designed to work with cellular technology, and wireless local area networks. Wireless modems are not yet perfected, but the technology is rapidly improving.