Digital Systems/Computers

What's so wonderful about digital?

You often hear how much better digital systems are than others. Digital musical instruments and recordings give very good sound, digital watches keep good time, digital tele-communication fast and easy to communicate, digital medical instruments for example the thermometer, blood pressure monitor, and others medical tech equipment and machine help the physician, transportations in space, land and sea they use digital equiptment and machines. Digital camera brings clear pictures, household equipments machines are digital. Computers are digital machines. But what does digital means.

Basically, a digital system is one that works with numbers. A digital watch display the time in changing numbers rather than the movement of hands over a dial. The other main kind of of system is called analog, and analog systems work by using things to represent numbers or quantities. As a watch may use hands to show the time, a thermometer uses the movement of a column of liquid to indicate temperatures and a gramophone records uses the wiggles of a groove to preserve sound waves. These are all analog system. Digital systems work first by measuring a changing-for example sound waves in digital recording- and then converting the measurements into strings of numbers. These numbers are in the form of codes and are usually handled by computers, which can deal with numbers very fast.

The numbers are then processed in some way; they may be recorded, for example. The system then takes the numbers and changes them back into required form, such as sound waves. Now, in all the processes that take place, the value of the numbers does not change, so that when they are changed back, the sound or whatever is produced is virtually identical to the original. Using a digital system the quality does not deteriorate.

Analog system change quantities into other quantities. In analog recording and broadcasting, for example, sound waves are changed into varying electric currents in wires, radio signals transmitted through the air, magnetic patterns on tape or wiggles in the grooves of a record, and then back into sound. All these changes degrade the sound, so that it is not as good as the original.

Digital computers solve problems and do other tasks by counting, comparing, and rearranging digits in the arithmetic/logic unit. All data, whether numbers, letters, or symbols, are represented by digits. Digital computers commonly use the digits of the binary numeration system. Unlike the familiar number system, which uses 10 digits, the binary system uses only two digits: 0 and 1. These binary digits called bits, can be easily represented by thousands of tiny electronic circuits of digital computer.The circuits operate much like an ordinary electric switch. When the switch is off, it corresponds to the binary digits 0. When the switch is on, it corresponds to the digit 1.

An electronic digital computer is able to perform all the basic arithmetic operations because binary digits, like decimal numbers, can be added, subtracted, multiplied, and divided. To solve a problem, it carries out these operations automatically one after the other according to the program stored in its memory.

Most digital computers are general-purpose computers. They can be programmed to handle all sorts of complicated, multistep tasks. These computers are so widely used that the word computer often means a general-purpose digital computer.