Specifications

ANALOGUE VS. DIGITAL

Analogue comes from two Greek words loosely meaning “word for word,” as in a translation. The

adjective is a way of describing information in one understandable way analogous to or similar to

the actual way. The description is often applied to the use of a “picture for picture” instead of a

“word for word” translation. For example, an analogue clock has hands that make a complete

circuit in a minute or in an hour or in half a day, depending on which hand it is. The hands

continually go around just as the earth turns completely around on its axis in a day. Photographs

are analogue recordings of the light that entered a camera

lens and altered the chemistry on

photographic film on the back wall. Reproductions can be made onto paper from the film or even

from the paper. The problem with this system is that the information gets mixed up with the flaws

of the medium. A clock hand that does not keep up with the other hands gives inaccurate

information. Dust or a scratch on photographic film or on a photograph reproduced from the film

will show up on all copies produced from them.

Digital recording is a method that avoids these flaws. Digital recording does not try to draw or

imitate the information that is being saved. Instead, it converts the information into a mathematical

code that ignores the flaws of whatever medium is storing the data. To use an analogy, a canvas

painting of a landscape records the landscape with all the “flaws” of canvas and paint texture

(those “flaws” that make a painting an inaccurate but artistic impression). If oil is spilled on the

painting, it is difficult to restore what was there because the oil becomes part of the record. If,

however, someone recorded the landscape with a “paint-by-number” scheme in great detail, the oil

would not matter. The oil stain had no numbers assigned to it, so the artist could reproduce the

landscape by following the number code exactly. The more numbers involved, the more accurate

and detailed the reproduction would be—and every copy would be almost identical to the original.

The word digital refers to digits or numbers. It comes from the Latin word digitus, or “finger,”

because everyone learns to count on his or her fingers. We have ten fingers; so our common

numbering system is to the base 10 and uses ten digits—0 to 9. The mathematical code used in

digital recordings is very intricate and needs computer chips to encode and decode, but computers

don’t have fingers. They have transistors that recognize only two states: on/off (or “0/1,”

“change/no change,” “+/-,” etc.). Computer engineers use the binary numbering system for

computers, a numbering system to the base 2 that needs only two numbers, 0 and 1, to construct

any value. Expressing the same number 3723 in both our common decimal system (10) and the

binary (2) numbering system shows the differences between the two.

3,723

The decimal system uses digits 0 to 9. Each column is 10X greater than the one on its right.

1 millions 100 thousands 10 thousands thousands hundreds tens ones

0 0 0 3 7 2 3 = 3,723

The binary system uses only digits 0 and 1. Each column is 2X greater than the one on its

right.

2048’s 1024’s 512’s 256’s 128’s 64’s 32’s 16’s eights fours twos ones

1 1 1 0 1 0 0 0 1 0 1 1

2,048 + 1,024 + 512 + 0 + 128 + 0 + 0 + 0 + 8 + 0 + 2 + 1 = 3,723

”Camera“ is Italian for “room.” In 1558 Battista della Porta constructed a darkened room with a lens fitted into a small hole in one wall.

Light entered the lens and produced an upside down image on the opposite wall of whatever was visible through the lens. He called the

room his “camera obscura.” Film cameras work on the same principle, and photosensitive film rests on the “back wall” of the room.