Survey of Broadcasting: Assignment 1, Question 1: Describe the five general steps of signal processing–Videos

Posted on June 21, 2011. Filed under: Audio, Broadcasting, Communications, Digital Communication, Radio, Signal Processors, Sound, Television | Tags: , , , , , , |

1. Describe the five general steps of signal processing.

Roger Waters – Radio KAOS – Radio Waves

    The five general steps in signal processing are as follows:

  1. Signal generation
  2. Signal amplification and processing
  3. Signal transmission
  4. Signal reception
  5. Signal storage.

Step 1 Signal Generation: Signal generation is the conversion or transduction of the sound or light waves from the source into electrical energy which corresponds to the frequency of the original source. The audio signal may be generated  mechanically using a microphone or turntable to create an analog of the original sound signal such as a phonograph record or audio cassette.  Microphones are used to transduce the physical energy of music and voice into electrical energy.The audio signal may be generated electromagnetically using tape recorders.The audio signal may also be generated digitally by using laser optics to create a binary or digital equivalent of the original sound.  Television signal generation requires electronic line-by-line scanning of an image using an electron beam to scan each element of the picture. The image is subsequently retraced by the television receiver.

Step 2 Signal Amplification and Processing: Audio and video signals are amplified and mixed using audio consoles and video switchers. After the audio signal has been converted from a physical sound wave into an electrical or digital facsimile, the audio signal must be amplified to boost the signal and processed including the mixing, combining and routing for broadcast transmission and/or recording. Sound sources are combined at the mixing board. The amplified sound may be fine tuned using equalizers and special effects. The switcher is used to mix TV signals and put the desired picture on the air. A special effect generator is used to add transitions, split screen and keying. Digital video editing and effects can also be produced using computer software such as Adobe Premiere Pro and After Effects.

Step 3 Signal Transmission: The electronic signal is superimposed  by a modulation process on a carrier wave  generated or propagated by the radio station on its assigned frequency. The generated sound wave may travel by ground, sky and direct waves. Radio waves occupy a segment of the electromagnetic spectrum. AM radio channel frequencies are divided into three main types: clear channels, regional channels and local channels. FM channel frequencies are classified by antenna height and power. Stereo broadcasting and other nonbroadcast services are accomplished with the wide bandwidth of the FM channel. Digital radio is satellite-based  or in-band on channel. Television signal transmission includes over-the-air broadcasting using the electromagnetic radiation on the VHF and UHF portions of the spectrum or by wire through a cable system using coaxial cable that can carry programming on more than 100 channels.. New transmission technologies used for transmission and distribution include satellite and fiber optics for digital signals.

Step 4 Signal Reception: After the radio signal has been transduced, modulated and transmitted, the radio waves are picked up on a radio receiver where they are transduced or converted by the speaker system back into sound waves. The characteristics of the electromagnetic spectrum and modulation  method used in transmission determine the type of radio receiver needed to convert the signal back into sound waves.There are several types of radio receivers including AM, AM stereo, FM, shortwave, and multiband. These receivers can be equipped with either analog tuners or a digital system. For moving images both large and small-screen TVs are now receiving high-definition television vision signals. 

Step 5 Signal Storage: Both audio and video technology is used in the storage and retrieval of sounds and moving images.  Audio or video signals are transduced or converted for storage and eventual playback or rebroadcast. The storage medium have included glass discs, wire, vinyl, magnetic type, compact disc, video tapes, digital storage media such as digital versatile discs (DVDs) and computer hard drives including high-capacity disc drives.

Roger Waters – Radio KAOS – Tide Is Turning

Background Articles and Videos


Amplitude modulation tutorial & AM radio transmitter circuit 


The Professor – How does a radio work?


AM Modulation and Demodulation Part 1


Introduction to Radio Waves Training Course


High Definition Television (HDTV) : Difference Between High & Standard


Roger Waters – Radio KAOS – Intro

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Chapter 6–Radio

Posted on June 11, 2010. Filed under: Communications, Mass Media, Radio | Tags: , , , , |


1. Describe the effects that narrowcasting could have on the radio industry. Give specific examples.

Narrowcasting is the identification of a specific audience segment and programming for it.  Instead of broadcasting to the general public, the narrowcast is aimed or targeted to a specific audience. The effects of narrowcasting are that overall costs usually go down and the efficiency of advertising go up. Companies with specific products such as guns, cars, investments and health supplements can place their ads on the radio shows that cover these products and services.

Narrowcasting on radio includes radio shows on cars, health care, gardening, guns, politics, investments, real estate and sports. For example owners of gun and cars can listen to radio shows that focus or target gun and care owner audiences.

The Rise of Narrowcasting

“…The advancement of technology and the shift from industrial to information society has demassified production. Marketers are interested to satisfy the individual needs of each person as opposed to the need of society. In the filed of media this new trend of segmentation leads to narrowcasting. Narrowcasting acts as the binary opposite to the conventional (mass-audience) broadcasting. The three major broadcasting networks (ABC, NBC and CBS avoided programming content that might appeal only to a small segment of the mass population and succeeded in their goal by reaching nearly 90% (combined) of the television viewing audience on a regular basis (Massey, 2001 ). With the invention of narrowcasting individuals are able to view, read and listen to information that interests their personal needs and taste. Narrowcasting also enables marketers to categorize and target their advertisement easily to the specified demographic audience. While both consumers and producers seem to benefit from this new trend, narrowcasting has the tendency to weaken the perspective of individuals. ..”

2. Compare Gordon McLendon’s formats of the 1950s to three of the most popular formats today. How are they similar? How are they different?

Gordon McLendon combined music and news into a radio show format with a predictable rotation of 20-minute segments. McLendon created the Top 40 format for music, which played the top-selling hits with brief interruptions by a disc jockey or a newscast.

Today, the most popular formats are  news/talk, country, and religious/teaching.

3. How has the Telecommunications Act of 1996 affected the industry? What changes has it brought about?

The Telecommunications Act of 1966 removed the limit on the number of radio stations a company could own and in local markets, the number of radio station a company could own was a function of the size of the market. The Telecommunications Act of 1996 also allows for radio and television  station cross-ownership as well as cable outlet in the same market. The result was more consolidation or concentration of ownership so that many companies now own more that 100 radio stations as well as television  stations and cable outlets.

The Telecommunications Act of 1966 led directly to the concentration of media ownership including the elimination of many local  independent and alternative media outlets and fewer broadcasting companies competing in regional markets.

Telecommunications Act of 1996

4. What are some of the challenges involved with switching radio to digital audio broadcast? How will digital radio be better for listeners? Cite specific example from Chapter 8.

The challenges to switching  to digital audio broadcasting (DAB) include the cost of new broadcasting and receiving equipment (radios) and expanded program choices resulting in more competition for audiences and in turn advertisers. This means that should potential audiences become smaller, radio stations must compete with themselves.

Digital audio broadcast will be better for listeners for the audio quality and reception is much higher and more programs can be broadcast and received on a digital audio receiver or radio. Also additional information in the form of data and multimedia can be received as well. However, a DAB radio requires more power for portable radios.

Digital Audio Broadcasting Explained


DAB Digital Radio On Tomorrow’s World

DAB – The New Age Of Radio

Pure Move DAB Radio Review


Satellite digital radio will be better for listeners for it offers many more channels of programming with limited advertising on some stations and no advertising on others. However listeners of satellite digital radio must pay a monthly fee to hear uninterrupted programming. This service also requires the purchase of a radio with a small satellite radio receiver


DAB – The New Age Of Radio – Interviews



Digital radio

“…Digital radio describes radio technologies which carry information as a digital signal, by means of a digital modulation method. The most common meaning is digital audio broadcasting technologies, but the topic may also cover TV broadcasting, two-way digital wireless communication technologies, and radio delivered via the Internet. The acronym DAB (Digital Audio Broadcasting) is synonymous with the Eureka 147 standard. …”

“…United States

The United States has opted for a proprietary system called HD Radio(TM) technology, a type of in-band on-channel (IBOC) technology. Transmissions use orthogonal frequency-division multiplexing, a technique which is also used for European terrestrial digital TV broadcast (DVB-T). HD Radio technology was developed and is licensed by iBiquity Digital Corporation. It is widely believed that a major reason for HD radio technology is to offer some limited digital radio services while preserving the relative “stick values” of the stations involved and to insure that new programming services will be controlled by existing licensees.

The FM digital schemes in the U.S. provide audio at rates from 96 to 128 kilobits per second (kbit/s), with auxiliary “subcarrier” transmissions at up to 64 kbit/s. The AM digital schemes have data rates of about 48 kbit/s, with auxiliary services provided at a much lower data rate. Both the FM and AM schemes use lossy compression techniques to make the best use of the limited bandwidth.

Lucent Digital Radio, USA Digital Radio (USADR), and Digital Radio Express commenced tests in 1999 of their various schemes for digital broadcast, with the expectation that they would report their results to the National Radio Systems Committee (NRSC) in December 1999.[3] Results of these tests remain unclear, which in general describes the status of the terrestrial digital radio broadcasting effort in North America. Some terrestrial analog broadcast stations are apprehensive about the impact of digital satellite radio on their business, while others plan to convert to digital broadcasting as soon as it is economically and technically feasible.[citation needed]

While traditional terrestrial radio broadcasters are trying to “go digital”, most major US automobile manufacturers are promoting digital satellite radio. HD Radio technology has also made inroads in the automotive sector with factory-installed options announced by BMW, Ford, Hyundai, Jaguar, Lincoln, Mercedes, MINI, Mercury, Scion, and Volvo. Beyond the U.S., commercial implementation of HD Radio technology is gaining momentum around the world.[4]

Satellite radio is distinguished by its freedom from FCC censorship in the United States, its relative lack of advertising, and its ability to allow people on the road to listen to the same stations at any location in the country. Listeners must currently pay an annual or monthly subscription fee in order to access the service, and must install a separate security card in each radio or receiver they use.

Ford and Daimler AG are working with Sirius Satellite Radio, previously CD Radio, of New York City, and General Motors and Honda are working with XM Satellite Radio of Washington, D.C. to build and promote satellite DAB radio systems for North America, each offering “CD quality” audio and about a hundred channels.[citation needed]

Sirius Satellite Radio launched a constellation of three Sirius satellites during the course of 2000. The satellites were built by Space Systems/Loral and were launched by Russian Proton boosters. As with XM Satellite Radio, Sirius implemented a series of terrestrial ground repeaters where satellite signal would otherwise be blocked by large structures including natural structures and high-rise buildings.

XM Satellite Radio has a constellation of three satellites, two of which were launched in the spring of 2001, with one following later in 2005. The satellites are Boeing (previously Hughes) 702 comsats, and were put into orbit by Sea Launch boosters. Back-up ground transmitters (repeaters) will be built in cities where satellite signals could be blocked by big buildings.

The FCC has auctioned bandwidth allocations for satellite broadcast in the S band range, around 2.3 GHz.

The perceived wisdom of the radio industry is that the terrestrial medium has two great strengths: it is free and it is local.[citation needed] Satellite radio is neither of these things; however, in recent years, it has grown to make a name for itself by providing uncensored content (most notably, the crossover of Howard Stern from terrestrial radio to satellite radio) and commercial-free, all-digital music channels that offer similar genres to local broadcast favorites. …”


5. Cite the landmarks in the development of the radio industry from 1835 to today. (See “Timeframe,” Chapter 8.) What did each development contribute to the evolution of the radio industry?

1835: Samuel F.B. Morse first demonstrates his electromagnetic telegraph system in America.

1899: Guglielmo Marconi first uses his wireless radio to report the America’s Cup race.

1907: Lee de Forest introduces the Audio tube, which improves the clarity of radio signal reception.

1920: Station KDKA in Pittsburg goes on the air as the nation’s first commercial radio station.

1934: Congress establishes the Federal Communications Commission to regulate broadcasting.

1936: Edwing H. Armstrong licenses frequency modulation (FM).

1938: Mercury Threater on the Air broadcasts “War of the Worlds”: demonstrating how quickly broadcast misinformation can cause a public panic.

1959: Gordon McLendon introduces format radio at station KABL in San Francisco.

1960: The Manhattan Grand Jury indicts disc jockey Alan Freed for payola.

1970: National Public Radio (NPR) goes on the air.

Background Information

Radio History


‘ON THE AIR’ 1937 – How Radio Works

Part 1 of 3 The Secret Life of the Radio



Part 2 of 3 The Secret Life of the Radio


Part 3 of 3 The Secret Life of the Radio


6. How did each of these people contribute to the evolution of American radio?

a. Guglielmo Marconi was an inventor who developed and promoted a radio telegraph system.

b. Reginald Fessenden experimented in radio and sent the first voice and music radio broadcast  on December 24, 1906

 c. Lee de Forest perfected a glass bulb he called the Audion that could detect radio waves and improved the clarity of radio signal reception

A small bit of Radio History, Lee De Forest Audion, Marconi


Background Information 

Guglielmo Marconi


Guglielmo Marconi

“…Guglielmo Marconi (Italian pronunciation: [ɡuʎˈʎɛːlmo marˈkoːni]; 25 April 1874– 20 July 1937) was an Italian inventor, best known for his development of a radio telegraph system, which served as the foundation for the establishment of numerous affiliated companies worldwide. He shared the 1909 Nobel Prize in Physics with Karl Ferdinand Braun “in recognition of their contributions to the development of wireless telegraphy”[1][2][3] and was ennobled in 1924 as Marchese Marconi. …”

Reginald Fessenden

“…Reginald Aubrey Fessenden (October 6, 1866 – July 22, 1932) was a Canadian inventor who performed pioneering experiments in radio, including early—possibly the first— transmissions of voice and music. In his later career he received hundreds of patents for devices in fields such as high-powered transmitting, sonar, and television. …”

Lee De Forest

“…Lee De Forest (August 26, 1873 – June 30, 1961) was an American inventor with over 180 patents to his credit. De Forest invented the Audion, a vacuum tube that takes relatively weak electrical signals and amplifies them. De Forest is one of the fathers of the “electronic age”, as the Audion helped to usher in the widespread use of electronics. He is also credited with one of the principal inventions which brought sound to motion pictures.

He was involved in several patent lawsuits and he spent a substantial part of his income from his inventions on the legal bills. He had four marriages and 25 companies, he was defrauded by business partners, and he was once indicted for mail fraud, but was later acquitted.

He typically signed his name “Lee de Forest.”

He was a charter member of the Institute of Radio Engineers, one of the two predecessors of the IEEE (the other was the American Institute of Electrical Engineers).

DeVry University was originally named DeForest Training School, after Lee DeForest, by it’s founder Dr. Herman A. DeVry who was a friend and colleague of DeForest. …”

7. How did the Radio Act of 1912 set a precedent for American broadcasting?

Prior to 1911 there was no Federal regulatory authority over broadcasting. The Radio Act of 1912 created the Federal Radio Commission, the precursor to the Federal Communications Commission. The Federal Government was given more regulatory and enforcement powers over radio. The precedent was established that the airwaves were a public good and limited.

The Radio Act of 1912 required all amateur radio operators who wanted to broadcast or receive radio messages to be licensed. It also prohibited all amateur radio operators from transmitting over the main commercial and military frequencies.  The precedent of requiring all radio operators to be licensed applies to commercial radio stations that also must be licensed to broadcast their programs.

“…The Radio Act of 1912 is a United States federal law that required all seafaring vessels to maintain 24-hour radio watch and keep in contact with nearby ships and coastal radio stations. Part of the impetus for the act’s passage was the sinking of the RMS Titanic. Other factors included an ongoing conflict between amateur radio operators and the U.S. Navy and private corporations, that included the amateurs forging naval messages and issuing fake distress calls. The Wireless Ship Act of 1910 was seen as too weak to address the problems. The United States Congress considered six different proposals for replacing it in the period between 1910 and 1912, eventually enacting the 1912 Act.[1]

The act set a precedent for international and federal legislation of wireless communications. It was followed by the Radio Act of 1927.

The act required all amateur radio operators to be licensed and prohibited them from transmitting over the main commercial and military wavelengths. Amateurs were limited to transmitting signals that were below a wavelength of 200 meters. Besides being limited by wavelength, amateurs were also limited to location and operating hours.[2]

Implementing and enforcing the Act was the responsibility of the United States Secretary of Commerce and Labor. The United States Department of Commerce and Labor was empowered to impose fines and to revoke the licenses of those radio operators who violated the restrictions laid down by the Act.[1][3] …”

8. How did the following developments in radio affect the industry?

a. Blanket licensing: radio stations agreed to pay the American Society of Composers, Authors and Publishers (ASCAP) a fee in exchange for the use of all ASCAP-licensed music on the air.

b. Commercial sponsorship: radio stations sell advertising time to sponsors of radio programs to pay for the cost of broadcasting the program. Advertisers paid for programs directly through their advertising and in turn the American public paid for the programs indirectly by purchasing the goods and services of the advertisers.

c. Establishment of networks:A network is a collection of radio and television stations that broadcast programs, usually simultaneously. The establishment of networks provided a dependable source of programs and revenues.

9. Discuss the “War of the Worlds” broadcast and its effects upon its audience. How did it change people’s perceptions of radio?

The War of the Worlds was a radio drama based on H.G. Wells novel of The War of the Worlds that was broadcast on the CBS  radio network on October 31, 1938.

Many of the listeners actually believed that the planet was being attacked from outer space.

A captive audience with only one source of information can be temporarily fooled in believing something that appears credible. Many in the radio audience listening to the broadcast and who did not hear the disclosure that it was a fictional story, actually believed the nation was under attack.

The people’s perception of radio changed when they realized they could be fooled when they were a captive audience.

Orson Welles–War of The Worlds–Videos

The War of the Worlds

“…The War of the Worlds was an episode of the American radio drama anthology series Mercury Theatre on the Air. It was performed as a Halloween episode of the series on October 30, 1938 and aired over the Columbia Broadcasting System radio network. Directed and narrated by Orson Welles, the episode was an adaptation of H. G. Wells’ novel The War of the Worlds.

The first two-thirds of the 60-minute broadcast was presented as a series of simulated “news bulletins”, which suggested to many listeners that an actual alien invasion by Martians was currently in progress. Compounding the issue was the fact that the Mercury Theatre on the Air was a ‘sustaining show’ (it ran without commercial breaks), thus adding to the program’s verisimilitude. Although there were sensationalist accounts in the press about a supposed panic in response to the broadcast, the precise extent of listener response has been debated. In the days following the adaptation, however, there was widespread outrage. The program’s news-bulletin format was decried as cruelly deceptive by some newspapers and public figures, leading to an outcry against the perpetrators of the broadcast, but the episode secured Orson Welles’ fame.

Welles’ adaptation was one of the Radio Project’s first studies. …”

10. Define each of the following terms:

a. average quarter-hour: the average number of people listening to a station in any given fifteen minute period.

 b. cume is the cumulative audience or the estimated number of people listening to a station for five minutes or more in any given fifteen time period.

c. rating is the percentage of the total population that a station is reaching. 

d. share is the percentage of people listening to the radio that a station is reaching.

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