American television directory (1946)

Pedestal — The DC level or reference line on the complete television waveform above which the video information is inserted. Phase — The time relationship between maximum points of two recurrent electrical quantities such as voltage, current, etc. It is expressed in degrees of a circle. Phase-shift — Any changes taking place in the phase relations of current or voltage. Photoelectric cell — A light-sensitive cell capable of translating variations in the light falling upon it into corresponding variations in voltage, current or resistance. Photoelectric emission — The phenomenon of elec¬ trons being emitted from certain materials when they are exposed to light. Phasemajector — Allen B. DuMont Laboratories’ des¬ ignation for a tube used to generate television pic¬ ture signals. Pick-up — A program which is televised directly at a scene of action, such as an athletic event, a political convention, etc. Picture element — The smallest section of any given scene as reproduced by the cathode-ray tube at any given instant. Picture noise — Interference or undesired signals causing spots of light or other irregularities in the pattern of the received picture. Polarization — In television, the position of the trans¬ mitting antenna, i.e. horizontal or vertical. It is desirable that the receiving antenna correspond to the polarization of the transmitting antenna. Hori¬ zontal polarization is now standard for transmission in the United States. Vertical polarization is stand¬ ard in England. Projection television — A system of enlarging tele¬ vision pictures by a combination of lenses and mirrors that enable the picture to be projected on a screen. Radiator — That portion of an antenna from which the radio waves are actually emitted. Radio channel — A band of frequencies for radio communication in the radio frequency spectrum allo¬ cated to each station. By present television standards the channels are 6 megacycles wide. Radio frequency spectrum — All of the wave lengths or frequencies that may be used for the transmission by radio of energy or intelligence. Ready — A direction to a cameraman, instructing him to line up his camera for the next shot. Reflective optics — In television a system of mir¬ rors and lenses used in projection receivers. The Schmit system employed by RCA uses reflective optics. Reflector — Additional antenna elements used in an antenna system to prevent the pick-up of signals from one direction and to increase the pick-up from the opposite direction. Relay station — A radio station that re-broadcasts television or other radio programs in order to in¬ crease the service area. Sometimes known as a re¬ peater station. Return trace — Lines formed on the cathode-ray tube screen as the cathoderay beam moves back to its starting position. These are blanked out. Scanning — The process of analyzing successively, ac¬ cording to a predetermined method, the light values of picture elements constituting the total picture area. The cathode-ray beam scans the mosaic in the iconoscope and the fluorescent screen in the kinescope. Scanning line — A single continuous narrow strip containing high lights, shadows, and half tones which is established by the process of scanning. Screen — That part of a monitor or receiving set on which the television picture appears. Selectivity — The degree to which a radio receiver is capable of reproducing wanted signals from one station while rejecting all unwanted signals from other stations on adjacent channels. Sensitivity — A measure of the ability of a radio or television receiver to reproduce weak signals with satisfactory volume or intensity. Shading — Technique of adjusting the light distribu¬ tion in the image produced by the television camera. One of the monitoring operations necessary when Iconoscope cameras are used. Side bands — Those groups of frequencies higher and lower than the carrier that contain the intelligence being transmitted and produced by modulation. Signal — Electrical impulses corresponding to sound or picture information being transmitted. Special effects — Graphic material introduced into a studio presentation, particularly animated titles, miniatures, mechanical gadgets, etc. Camera or light¬ ing tricks used to create certain illusions. Special events — Programs not regularly scheduled, particularly those “picked up” by mobile equipment units. Spectrum — A band or range of frequencies. Usually used to designate the entire range of radio fre¬ quencies available for transmission. Spot — The visible point of light formed by the cathode-ray beam as it strikes the fluorescent screen of the kinescope tube. Stratovision — A proposed system of establishing net¬ work television by means of airplanes circling above certain points and carrying both relay and local broadcasting equipment. Superimposure — A special effect in which the im¬ ages from two or more cameras occupy the screen simultaneously. Also called montage. Sweep — Uniform and repetitive action movement of an electron beam across the screen of a cathoderay tube, either vertically, horizontally or both. Switching — See Cut. Synchronization — Maintaining of one operation in step with another. In television, the term often refers to keeping the scanning beam at the transmitter in step with the electron beam at the receiver. Also used with reference to the correct coordination of picture and sound ; important when using recordings with pantomime action or graphic material with an off-screen speaker. "T.D." — Abbreviation for technical director, the station staff member who assists the director in the control room. Telecast — A television broadcast. Preferably called “a television broadcast,” the usage employed by the Federal Communications Commission. Telecine projector — A device used to televise mo¬ tion picture film. Telegenic — Having an attractive appearance when viewed on a television receiving set. Television — Literally, seeing at a distance. The transmission and reception of changing visual im¬ ages by means of radio waves traveling through space or over wires. Teleset — DuMont trade-marked name for home tele¬ vision receivers. Teletron — DuMont designation for a television re¬ ceiving tube developed by the Allen B. DuMont Laboratories, Inc. 12 television channels which had been assigned to the prewar system. This would make nationwide coverage pos¬ sible and at the same time give the viewer an opportunity to select from a larger number of programs. Even prewar color television broad¬ casts showed clearly that the pleasing effect, the clarity, and the texture of the images impressed the viewers im¬ mensely. The pictures, in natural colors, appeared to have a great deal of depth, an effect also apparent in present day color movies. Now Developing Receivers ■ Probably most people will be chiefly interested in the actual television re¬ ceiving sets. I would like to make it clear that CBS is not a manufacturer of commercial radio equipment, but we are developing two types of color re¬ ceivers in our laboratories for the bene¬ fit of the consumer and the set manu¬ facturers. One set is a small floor model and produces a picture approximately Test pattern — A drawing containing a group of lines and circles and other forms, transmitted for transmitter and receiver test purposes. Transmitter — Generally the equipment used for generating and sending radio signals of any type. Turnstile antenna — One or more layers of crossed horizontal half-wave antennas appropriately excited and arranged on a mast. Used in high frequency systems including television where a symmetrical pat¬ tern of radiation is desired. Tilting — A vertical sweep of a television camera. Trucking — A camera technique in which the shot is taken as the camera moves parallel to its moving object. Two-shot — A close-up or medium shot holding two persons, usually head and shoulders only, as the subject. Ultra-high-frequency — As recently standardized, uhf is any frequency of 300 megacycles or higher. Waves in this portion of the spectrum are called microwaves. Very-high-frequency — As recently standardized, vhf refers to frequencies between 30 and 300 megacycles. Vestigial sideband transmission — A system of trans¬ mission in which one of the generated sidebands is attenuated at the transmitter and radiated only in part. Vertical sweep — The downward movement of the scanning beam from top to bottom as a picture is televised. Visual transmitter — The radio equipment employed for transmitting the video or picture signal, as dis¬ tinct from the sound transmitting equipment. The combination makes up a complete television trans¬ mitter. Vertical centering — Control employed on a tele¬ vision receiver to regulate the position of the picture vertically on the screen. Vertical hold control — Control employed in a tele¬ vision receiver to adjust the field rate of the scan¬ ning to that of the transmitter. Video — That portion of the television signal that contains the picture information. Used as a prefix to the names of television parts or circuits that handle picture signals. (Latin: “I see.”) Viewing mirror — A mirror set at an angle in the lid of one type of television receiver. It reflects the image formed on the screen-face of a verticallymounted picture tube so that the image can be viewed by persons seated in front of the set. Yoke — A set of coils used around the neck of a cathode-ray tube to produce horizontal and vertical deflection of the electron beam. Used for electro¬ magnetic deflection. the same size as a full page in Time magazine. The larger and more expen¬ sive model wrill furnish an image which is about 20 inches wide, or about the size of a full newspaper page. It is estimated that color television receivers will be only slightly more ex¬ pensive than black and white receivers. Many have asked when this new sys¬ tem of television will be available for the public. Development work and con¬ struction have advanced sufficiently to permit field testing early in 1946. After successful completion of the tests man¬ ufacturers will be in a position to start production of the receiving sets for the home. Thus, this most advanced television system, transmitting images in full col¬ ors and utilizing the progress made during the war in the field of electron¬ ics, will guard against receivers becom¬ ing obsolete for a long time to come. This is a prerequisite for the establish¬ ment of a nationwide television service. COLOR TELEVISION f Continued from page 32) 114