Radio broadcasting

Video is an electronic medium for the recording, copying, playback, broadcast, and display of moving-image media. Video was first developed for mechanical television systems, which were quickly replaced by cathode-ray tube (CRT) systems, which, in turn, were replaced by flat-panel displays.

Video systems vary in display resolution, aspect ratio, refresh rate, color reproduction, and other qualities. Both analog and digital video can be carried on a variety of media, including radio, magnetic tape, optical discs, computer files, and network streaming.

Television (TV) is a telecommunication medium for transmitting moving images and sound. Additionally, the term can refer to a physical television set rather than the medium of transmission. Television is a mass medium for advertising, entertainment, news, and sports. The medium is capable of more than "radio broadcasting", which refers to an audio signal sent to radio receivers.

Television became available in crude experimental forms in the 1920s, but only after several years of further development was the new technology marketed to consumers. After World War II, an improved form of black-and-white television broadcasting became popular in the United Kingdom and the United States, and television sets became commonplace in homes, businesses, and institutions. During the 1950s, television was the primary medium for influencing public opinion. In the mid-1960s, color broadcasting was introduced in the U.S. and most other developed countries.

A digital audio workstation (DAW /dɔː/) is an electronic device or application software used for recording, editing and producing audio files. DAWs come in a wide variety of configurations, from a single software program on a laptop, to an integrated stand-alone unit, all the way to a highly complex configuration of numerous components controlled by a central computer. Regardless of configuration, modern DAWs have a central interface that allows the user to alter and mix multiple recordings and tracks into a final produced piece.

DAWs are used for producing and recording music, songs, speech, radio, television, soundtracks, podcasts, sound effects and nearly every other kind of complex recorded audio.

Broadcasting is the distribution of audio and audiovisual content to dispersed audiences via an electronic mass communications medium, typically using the electromagnetic spectrum (radio waves), in a one-to-many model. Broadcasting began with AM radio, which became popular around 1920 with the spread of vacuum tube radio transmitters and receivers. Before this, most implementations of electronic communication (early radio, telephone, and telegraph) were one-to-one, with the message intended for a single recipient. The term broadcasting evolved from its use as the agricultural method of sowing seeds in a field by casting them broadly about. It was later adopted for describing the widespread distribution of information by printed materials or by telegraph. Examples applying it to "one-to-many" radio transmissions of an individual station to multiple listeners appeared as early as 1898.

Over-the-air broadcasting is usually associated with radio and television, though more recently, both radio and television transmissions have begun to be distributed by cable (cable television). The receiving parties may include the general public or a relatively small subset; the point is that anyone with the appropriate receiving technology and equipment (e.g., a radio or television set) can receive the signal. The field of broadcasting includes both government-managed services such as public radio, community radio and public television, and private commercial radio and commercial television. The U.S. Code of Federal Regulations, title 47, part 97 defines broadcasting as "transmissions intended for reception by the general public, either direct or relayed". Private or two-way telecommunications transmissions do not qualify under this definition. For example, amateur ("ham") and citizens band (CB) radio operators are not allowed to broadcast. As defined, transmitting and broadcasting are not the same.

In radio communications, a radio receiver, also known as a receiver, a wireless, or simply a radio, is an electronic device that receives radio waves and converts the information carried by them to a usable form. It is used with an antenna. The antenna intercepts radio waves (electromagnetic waves of radio frequency) and converts them to tiny alternating currents which are applied to the receiver, and the receiver extracts the desired information. The receiver uses electronic filters to separate the desired radio frequency signal from all the other signals picked up by the antenna, an electronic amplifier to increase the power of the signal for further processing, and finally recovers the desired information through demodulation.

Radio receivers are essential components of all systems based on radio technology. The information produced by the receiver may be in the form of sound, video (television), or digital data. A radio receiver may be a separate piece of electronic equipment, or an electronic circuit within another device. The most familiar type of radio receiver for most people is a broadcast radio receiver, which reproduces sound transmitted by radio broadcasting stations, historically the first mass-market radio application. A broadcast receiver is commonly called a "radio". However radio receivers are very widely used in other areas of modern technology, in televisions, cell phones, wireless modems, radio clocks and other components of communications, remote control, and wireless networking systems.

Old media, also called traditional media or legacy media, are the mass media institutions that dominated prior to the internet, particularly print media, film studios, music studios, advertising agencies, radio broadcasting, and television. Old media institutions are centralized and communicate with one-way technologies to a generally anonymous mass audience.

Old media are often contrasted with new media, which are typically computer- or smartphone-based, and are to some extent interactive and comparatively decentralized. These new media enable people to telecommunicate with one another peer-to-peer or through social media platforms, with widespread use and availability through the internet.

In electronics and telecommunications, a radio transmitter or just transmitter (often abbreviated as XMTR or TX in technical documents) is an electronic device which produces radio waves with an antenna with the purpose of signal transmission to a radio receiver. The transmitter itself generates a radio frequency alternating current, which is applied to the antenna. When excited by this alternating current, the antenna radiates radio waves.

Transmitters are necessary component parts of all electronic devices that communicate by radio, such as radio (audio) and television broadcasting stations, cell phones, walkie-talkies, wireless computer networks, Bluetooth enabled devices, garage door openers, two-way radios in aircraft, ships, spacecraft, radar sets and navigational beacons. The term transmitter is usually limited to equipment that generates radio waves for communication purposes; or radiolocation, such as radar and navigational transmitters. Generators of radio waves for heating or industrial purposes, such as microwave ovens or diathermy equipment, are not usually called transmitters, even though they often have similar circuits.

Public broadcasting (or public service broadcasting) is radio, television, and other electronic media whose primary mission is public service with a commitment to avoiding political and commercial influence. Public broadcasters receive funding from diverse sources including license fees, individual contributions and donations, public financing, and corporate underwriting.

A public service broadcaster should operate as a non-partisan, non-profit entity, guided by a clear public interest mandate. Public service broadcasters must be safeguarded from external interference—especially of a political or commercial nature—in matters related to governance, budgeting, and editorial decision-making. The public service broadcasting model relies on an independent and transparent system of governance, encompassing key areas such as editorial policy, managerial appointments, and financial oversight.

AM broadcasting is radio broadcasting using amplitude modulation (AM) transmissions. It was the first method developed for making audio radio transmissions, and is still used worldwide, primarily for medium wave (also known as "AM band") transmissions, but also on the longwave and shortwave radio bands.

The earliest experimental AM transmissions began in the early 1900s. However, widespread AM broadcasting was not established until the 1920s, following the development of vacuum tube receivers and transmitters. AM radio remained the dominant method of broadcasting for the next 30 years, a period called the "Golden Age of Radio", until television broadcasting became widespread in the 1950s and received much of the programming previously carried by radio. Later, AM radio's audiences declined greatly due to competition from FM (frequency modulation) radio, Digital Audio Broadcasting (DAB), satellite radio, HD (digital) radio, Internet radio, music streaming services, and podcasting.

The music industry are individuals and organizations that earn money by writing songs and musical compositions, creating and selling recorded music and sheet music, presenting concerts, as well as the organizations that aid, train, represent and supply music creators. Among the many individuals and organizations that operate in the industry are: the songwriters and composers who write songs and musical compositions; the singers, musicians, conductors, and bandleaders who perform the music; the record labels, music publishers, recording studios, music producers, audio engineers, retail and digital music stores, and performance rights organizations who create and sell recorded music and sheet music; and the booking agents, promoters, music venues, road crew, and audio engineers who help organize and sell concerts.

The industry also includes a range of professionals who assist singers and musicians with their music careers. These include talent managers, artists and repertoire managers, business managers, entertainment lawyers; those who broadcast audio or video music content (satellite, Internet radio stations, broadcast radio and TV stations); music journalists and music critics; DJs; music educators and teachers; manufacturers of musical instruments and music equipment; as well as many others. In addition to the businesses and artists there are organizations that also play an important role, including musician's unions (e.g. American Federation of Musicians), not-for-profit performance-rights organizations (e.g. American Society of Composers, Authors and Publishers) and other associations (e.g. International Alliance for Women in Music, a non-profit organization that advocates for women composers and musicians).

A media market, broadcast market, media region, designated market area (DMA), television market area, or simply market, is a region where the population can receive the same (or similar) television and radio station offerings, and may also include other types of media such as newspapers and internet content. They can coincide with or overlap with one or more metropolitan areas, though rural regions with few significant population centers can also be designated as markets. Conversely, very large metropolitan areas can sometimes be subdivided into multiple segments. Market regions may overlap, meaning that people residing on the edge of one media market may be able to receive content from other nearby markets. They are widely used in audience measurements, which are compiled in the United States by Nielsen Media Research. Nielsen has measured both television and radio audiences since its acquisition of Arbitron, which was completed in September 2013.

Markets are identified by the largest city, which is usually located in the center of the market region. However, geography and the fact that some metropolitan areas have large cities separated by some distance can make markets have unusual shapes and result in two, three, or more names being used to identify a single region (such as Wichita–Hutchinson, Kansas; Chico–Redding, California; Albany–Schenectady–Troy, New York; and Harrisburg–Lebanon–Lancaster–York, Pennsylvania).

Lee de Forest (August 26, 1873 – June 30, 1961) was an American inventor, electrical engineer and an early pioneer in electronics of fundamental importance. He invented the first practical electronic amplifier,the three-element "Audion" triode vacuum tube in 1908. This helped start the Electronic Age, and enabled the development of the electronic oscillator. These made radio broadcasting and long distance telephone lines possible, and led to the development of talking motion pictures, among countless other applications.

He had over 300 patents worldwide, but also a tumultuous career – he boasted that he made, then lost, four fortunes. He was also involved in several major patent lawsuits, spent a substantial part of his income on legal bills, and was even tried (and acquitted) for mail fraud.

A sign-on (or start-up in Commonwealth countries except Canada) is the beginning of operations for a radio or television station, generally at the start of each day. It is the opposite of a sign-off (or closedown in Commonwealth countries except Canada), which is the sequence of operations involved when a radio or television station shuts down its transmitters and goes off the air for a predetermined period; generally, this occurs during the overnight hours although a broadcaster's digital specialty or sub-channels may sign-on and sign-off at significantly different times than its main channels.

Like other television programming, sign-on and sign-off sequences can be initiated by a broadcast automation system, and automatic transmission systems can turn the carrier signal and transmitter on/off by remote control.