TV signal transmission system is point to point and make a line by line by an electron beam (Electron Beam) or light Kathoda (Cathode beam) as read from left to right and once to the right side must be left back again quickly and shifted vertically downward read the following sentence under it, so after the end of the sentence until the bottom side must get back quickly onto the next page to read the sentence. At the time of re-moving horizontally from right-left and from below upwards, the electron beam is extinguished.
Before the era of television technology have been known Media Movie Theaters that use the big screen, compared with Vertical Horizontal size is 2: 1 or more technical term is Aspect Ratio (H / V) = 2 / 1, taken from the characteristics of the sensitivity of human eye sight (Human psychology weakness) that the human eye is more sensitive than the horizontal viewing angle of view vertically.
The term full image in a film known as Frame, early film technology uses the turn of the image as much as 18 frames per second, while the film is used up to now uses 24 frames per second.
Television technology uses the same term for the FRAME picture in one screen, based on the dots picture elements that make a line by line which neatly represents the development of basic principles from point to point transmission of picture elements as the discovery of Paul Nipkow.
The line is a collection point for point and line by line collection is arranged in a glass screen as the system is called FRAME Scanning Scanning television or TV. At the beginning of TV technology is known there are 2 (two) scanning system, namely:
1) PROGRESS SCANNING, meaning the image for one frame is made with a regular arrangement of picture elements from point to point horizontally to make a line by line starting from the first line of the top side until the last line of the bottom side, and after the last line of the bottom side to move quickly upwards to re-create the first line.
2) Interlaced Scanning SCANNING or an insert, as the process of Scanning Progress system that makes the composition from point to point line by line from the top to the bottom side to make FRAME conducted 2 (two) times the scanning process, which means that to get done twice One Frame scanning process and every single time scanning to make the composition line by line from top side to bottom side as much as half of the diameter of the frame, and after half the number of lines have been arrayed on the side of the bottom line right back quickly made arrangement to one side over the line by line and a half next frame; on each make half the Frame was named as one FIELD, thereby frame = I + Field Field II.
Progress Scanning for TV system with the characteristics of the human eye where the eye nerve has not been able to capture the impression of the meaning of a picture of what is seen to have emerged the next image and to eliminate the impression of flicker; and enhance the impression of the image being viewed, the object of scanning performed twice with the same speed One form for each scanning field, and scanning the results of Field I and Field II, which form the A FRAME named as Interlaced Scanning.
For easy to understand given examples of the TV system used in Indonesia who draw the lines for one frame composed of 625 irregular line from the top to the bottom side of the moves made by horizontal lines at once to move vertically.
One Frame Field done scanning I create horizontal lines as much as half the number of lines of frame, then do the scanning Field II which makes half the number of lines the next frame, and the time I used to field the same as the Field II.
Frame (625 lines) = Field I (312.5 lines) + Field II (312.5 lines)
Field I is the composition line by line as much as half a frame from the side line at the top to the bottom side of the line numbers given ODD numbers, meaning that on any given horizontal scanning lines of odd numbers of indices such as the number of scanning lines 1, 3, 5 ff. Field so I can say as ODD or ODD FIELD FIELD.
Field II is the arrangement of line by line as much as half the next frame from the very top to the bottom side of the line are given index numbers evens numbers, meaning that at each horizontal scanning lines are numbered even numbers 2, 4, 6 ff. Field II so that it can be said as evens or EVEN FIELD FIELD.
Thus the composition of the odd-numbered lines of Field I (Odd Field) interspersed with a scanning line Field II (Field Events) will produce a line arrangement of serial numbered 1, 2, 3, 4, 5, 6 etc. to form a number line TV system that used or FRAME.
Time to do the scanning process to form the first line of the upper hand until the last line of the bottom side of each field is required for the same time, meaning that Field Field II = I = turnover frequency = frequency of the image grid (City Source) is to use time of network systems generating electrical energy from the countries concerned.
As examples of TV system in Indonesia that use the number of scanning lines of 625 lines and follow the European regulations as recommended by the International Telecommunication Union (ITU), namely regulations CCIR (Consultative Committee Internationale des Radiocommunication), with 50 Hertz power grid, as the example below will make it easier understanding the use of frames per second television system that used our country, as follows:
Given: PAL TV system, Aspect Ratio (H / V) = 4 / 3, with 625 lines Interlaced Scanning.
Asked: Frames per second.
Answer:
PAL TV system uses 625 lines, Interlaced scanning system and Electrical Frequency 50 Hertz
f = 1 / t
50 (Hertz) = 1 / t
50 t = 1
t = 1 / 50 (seconds)
Frequency is the number of revolutions per second or
f = frequency (Hertz) - cycles per second
f = 1 / t
t = time (second)
FRAME FIELD = FIELD I + II
Field Field II = I = t = 1 / 50 sec
FRAME = 2 Fields
= 2 x 1 / 50 sec
FRAME = 1 / 25 sec
25 FRAME = 1 second or
1 Second = 25 Frames
This means that in 1 second used 25 frames.
Television as the development of radio broadcasting media have targeted the target (audience) is more extensive (Mass Audiences) where the terms of the television technology that must be considered include:
a) Must be seen in space without having to turn off the lights or lighting during the day without having to darken the room.
b) The image must be smooth and sharp.
c) Image is not blinking (flickers).
d) Must be seen by two or more viewers than a short distance.
e) It can be tuned by a layman.
If the movie uses the size of the screen with Aspect Ratio (H / V) = 2 / 1, then the required size for television Aspect Ratio by considering how much TV viewing distance is right?
Figure shows the calculation to obtain the correct distance to watch TV, where point A is the position of the viewer's eye and the line AF is the distance to the plane of viewers TV screen. By calculating the angle (Alpha) against right-angled triangle AFD AF will get a longer length of 5 x against Diagonal Screen Glass TV (AF = 5 CD = 5 BE). This calculation produces the TV screen size is known as the Aspect Ratio or the ratio of horizontal to vertical (H / V) is 4 / 3.