Tv Broadcasting

Front 1

Antenna

Back 1

A structure associated with the transition between a guided wave such as may exist in a transmission line and a free-space wave.

Front 2

Omnidirectional or Non-directional Antenna

Back 2

An antenna designed to have a circular pattern with a circularity of the order of +1dB to +2dB.

Front 3

Directional Antenna

Back 3

An antenna that is designed to be directional.

Front 4

AHAT

Back 4

The average of the antenna heights above the terrain from 3 to 16 km from the antenna for the 8 directions.

Front 5

Antenna Power Gain

Back 5

The square of the ratio of the root mean-square free space field intensity produced at 1 kilometer in the horizontal plane.

Front 6

Antenna Terminal

Back 6

An accessible point where the entire antenna including the distributing system terminates into one feed line at the design characteristic impedance.

Front 7

Aspect Ratio

Back 7

The ratio of picture width to picture height as transmitted.

Front 8

Aural Transmitter

Back 8

The radio equipment for the transmission of the aural signal only.

Front 9

Aural Center Frequency

Back 9

The average frequency of the emitted wave without modulation.

Front 10

Azimuthal Pattern

Back 10

A plot of the free space radiated field intensity versus azimuth at a speci-field vertical angle with respect to a horizontal plane.

Front 11

Blanking Level

Back 11

The level of the signal during the blanking interval.

Front 12

Chrominance

Back 12

The colometric difference between any color and a reference color having a specific chromaticity.

Front 13

Chrominance Subcarrier

Back 13

The carrier which is modulated by the chrominance information.

Front 14

Color Transmission

Back 14

The transmission of color television signals which can be reproduced with different values of hue, saturation, and luminance.

Front 15

Effective Radiated Power

Back 15

The product of the antenna input power and the antenna power gain.

Front 16

Field

Back 16

Scanning through the picture area once in the chosen scanning pattern.

Front 17

Frame

Back 17

Scanning all of the picture area once.

Front 18

Free-Space Field Intensity

Back 18

The field intensity that would exist at a point in the absence of waves reflected from the earth or other reflecting objects.

Front 19

Frequency Modulation (FM)

Back 19

A system of modulation where the instantaneous radio frequency varies in proportion to the instantaneous amplitude of the modulating signal.

Front 20

Frequency Swing

Back 20

The instantaneous departure of the frequency of the emitted wave from the center frequency resulting from modulation.

Front 21

Horizontal Pattern

Back 21

An azimuthal pattern when the specified vertical angle is zero.

Front 22

Interlaced Scanning

Back 22

A scanning process in which successively scanned lines are spaced an integral number of line widths.

Front 23

Luminance

Back 23

Luminous flux emitted, reflected, or transmitted per unit solid angle per unit projected area of the source.

Front 24

Monochrome Transmission

Back 24

The transmission of television signals which can be reproduced in gradations of a single color only.

Front 25

Negative Transmission

Back 25

Where a decrease in initial light intensity causes an increase in the transmitted power.

Front 26

Peak Power

Back 26

The power over a radio frequency cycle corresponding in amplitude to synchronizing peaks.

Front 27

Percentage Modulation

Back 27

The ratio of the actual frequency swing the the frequency swing defined as 100 percent modulation.

Front 28

Polarization

Back 28

The direction of the electric field as radiated from the transmitting antenna.

Front 29

Reference Black Level

Back 29

The level corresponding to specified maximum excursion of the luminance signal in the black direction.

Front 30

Reference White Level of the Luminance Signal

Back 30

The corresponding to the specified maximum excursion of the luminance signal in the white direction.

Front 31

Scanning

Back 31

The process of analyzing successively, according to a predetermined method, the light values of picture elements constituting the total picture area.

Front 32

Scanning Line

Back 32

A single continuous narrow strip of the picture area containing highlights, shadows, and half-tones, determined by the process of scanning.

Front 33

Standard Television Signal

Back 33

A signal which conforms to the television transmission standards.

Front 34

Synchronization

Back 34

The maintenance of one operation in step with another.

Front 35

Television Broadcast Band

Back 35

The frequencies in the band extending from 54 to 890 MHz which are assignable to television broadcast stations.

Front 36

Television Broadcast Station

Back 36

A station in the broadcasting service transmitting simultaneously visual and aural signals intended to be received by the general public.

Front 37

Television Channel

Back 37

A band of frequencies 6 MHz wide in the television broadcast band and designated either by number or by the extreme lower and upper frequencies.

Front 38

Television Transmission Standards

Back 38

The standards which determine the characteristics of a television signal as radiated by a television broadcast station.

Front 39

Television Transmitter

Back 39

The radio transmitter or transmitters for the transmission of both visual and aural signals.

Front 40

Vertical Pattern

Back 40

A plot of free space radiated field intensity measured in the Fraunhofer region versus vertical angle in any specified vertical place which contains the center of the earth.

Front 41

Vestigial Sideband Transmission

Back 41

A system of transmission wherein the lower sideband is partially attenuated at the transmitter and radiated only in part.

Front 42

Visual Carrier Frequency

Back 42

The frequency of the carrier which is modulated by picture information.

Front 43

Visual Transmitter

Back 43

The radio equipment for the transmission of visual signal only.

Front 44

Visual Transmitter Power

Back 44

The peak power output when transmitting a standard television signal.