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Communications systems, such as radio and television, broadcast a high-frequency carrier wave modulated by a low-frequency signal. Modulation happens when you combine one signal into another to transmit information; demodulation occurs at the receiving end to recover the original signal. Commercial radio, computer data and fiber-optic communications use several forms of modulation to transmit and receive information.
The Icom IC-737A is a transceiver developed by the Japanese company Icom in 1993. You can use it to listen to radio broadcasts as well as transmit your voice using the included hand-held microphone. While Icom no longer manufactures the IC-737A, you may be able to find a used model; know the specifications of the device to understand all its capabilities.
The JVC TH-D60 digital home theater system adds some serious pop to your TV's audio. It features a built-in DVD player and numerous video outputs that let you connect it to an external display, and multiple video and audio inputs so you can add devices to the system. Understanding the inputs on the TH-D60 will ensure you hook up correctly the first time.
The Akai AT-A301 is an out-of-production AM/FM tuner. It has basic functions of band selection, 16 preset stations and preset scan, and it automatically selects FM stereo or mono mode -- note that all FM broadcasts are in stereo now. It has one set of RCA component outputs that can be connected to a receiver or amplifier. The unit was made in Japan. Mastering the functions of the Akai AT-A301 should take no longer than a few minutes.
In the world of circuitry the star (or "Y") and delta connections are two basic ways to connect three voltage sources together. While the star connection looks like a Y with each "ray" of the star leading to a voltage source, the delta connection looks like a triangle, with each side containing its own voltage source. The advantages of each configuration over the other in terms of stability and current makes them more or less appropriate depending on the situation.
Although satellite radio has become a popular medium, AM and FM radio stations are still where millions of listeners get their news and find their entertainment. AM radio is a popular haven for talk radio and news programming, while FM stations tend to focus on music. Most users can simply switch between the two broadcast spectra with the press of a button, but AM and FM radio broadcasts are substantially different.
The Wheelock UTA-1 is a universal telephone alert system that is used in loud locations where people normally can't hear a phone ring. It works similarly to a door bell; when somebody calls, the loud electronic ringer lets everybody know the phone is ringing. Installation can be completed in a few minutes and only requires a few tools. Once installed, select the ringer of your choice.
For some people, music players have become less of an accessory and more of an appendage. The most common variants of this electronic gadget require special power cords or a personal computer to charge. The downside to MP3s is they can run out of power and an electrical outlet isn't always around. Not only useful, but environmentally friendly at the same time, solar-powered music players are one of the top choices in chargers.
Germany's Grundig audio company was founded in the direct aftermath of World War II. As new production of radios was banned during Germany's initial post-war rebuilding, Grundig begun to provide repair services for existing radios. After designing a solid state, tubeless radio for manufacturing, Grundig grew and became known for its product's sound quality and innovations. The RTV 1020 was an audio receiver and radio tuner produced from 1977 to 1981.
Mobile communication is expanding rapidly. The first quarter of 2011 saw global sales of more than 428 million mobile devices, according to research firm Gartner. While voice communication remains the dominant mobile application, smartphones, which are capable of voice, video, Internet and data communication, represented almost a quarter of the sales reported by Gartner.
When a radio dial is turned to an AM or FM station, the radio receives separate signals that function quite differently. The abbreviations stand for the very way the signals work. AM means amplitude modulation. FM stands for frequency modulation.
Sound and light have long been linked in the development of modern science. Both propagate, or travel, through the air in complex combinations of waves, which can be broken down into basic components. Their speeds may differ (light travels at 186,282 miles per second, while sound travels at 343.2 metres per second at sea level), but the frequencies of sound can be compared directly to light waves.
The RCA 811K is an antique model of radio that was popular during the 1930s and 1940s in the United States. Users would place this radio in the center of their living rooms and gather around it each night to listen to news, sports and radio programs that provided entertainment. If you have an RCA 811K, you can still tune into some radio stations. You will need to use the special tuning controls on the front of the radio to get a station.
Mobile communication is the fastest growing communications technology in history. Cell phones, GPS systems, tablet computers and many more mobile devices are being adopted by all demographics for their wide spectrum of uses. Mobile communication is revolutionizing the commercial sector, enhancing people's personal lives and augmenting a rapidly expanding entertainment industry. All told, the uses of mobile communication are virtually endless, but can be considered in terms of several broad categories of contemporary use.
Radio antennas match the low impedance of a receiver to the high impedance of the free space medium through which radio waves percolate. Telescoping radio antennas are linear, retractable and are commonly used for radio devices, automobiles and cellular technology.
The Sony BDP-S301 is a 1080p Blu-ray disc player that was introduced in 2007. As of May 2011, this model is no longer being manufactured. The BDP-S301 offers 7.1 channels of surround sound, Bravia Theatre Sync technology that allows users to operate the player on other Sony A/V systems, and the capability of playing DVDs and CDs on the player.
The Sony BDP-S360 is a Blu-ray player from the popular electronics maker. The player supports Full HD 1080p video playback, Dolby and DTS audio codecs and BD-Live 2.0 support. The Blu-ray player can also playback and upscale DVD discs to high-definition. If your Blu-ray player is not working as it should, you can troubleshoot it to solve any problems.
Grundig is a German-based electronics manufacturer, with a variety of products sold across the globe. Among those is the S350DL deluxe AM/FM/shortwave radio. The S350DL is a lightweight, portable analog receiver built to provide excellent reception for radio enthusiasts, whether in your backyard, off on safari or in other remote locations.
The Grundig Satellite 500 is a high-end portable shortwave radio last manufactured in 1992, according to DXing.com. It's generally a high-quality unit with positive reviews, but the Satellite 500 can still have problems.
Pulse modulation methods may sound too scientific, but it is actually simple to understand. The first pulse modulation method appeared as Morse code that used specific combination of dots and dashes to communicate by telegraph. Several decades ago it was applied to microwave links to send digital data. Pulse modulation varies frequency, phase and amplitude of a waveform like a musician who modulates pitch, timing and volume of his instrument.
Eton Grundig S350DL Deluxe is a type of shortwave radio, and a shortwave radio generally picks up frequencies between the 3 and 30 Hz range, including emergency channels. You can also receive AM/FM stations on this radio. You can purchase Eton products from the Eton online store or from third-party retail partners.
An electric-powered amplified FM antenna improves FM reception, but can you use it to boost AM signals as well? To answer this question, a test was conducted using an electric FM antenna connected to an Optimus radio receiver.
MP3 players are becoming a major source of audio entertainment for many people. However, they can be difficult to use in the car without an FM converter or transmitter.
A tuner is a receiver used to bring in and play a specific signal from the jumble of signals all around. Resonant circuits in TVs and radios are responsible for collecting the signals needed to broadcast sound and image.
A shortwave radio allows you to hear radio broadcasts from much farther away than you could hear a normal AM or FM broadcast. Like other electronic devices, shortwave radios can have performance issues. The solutions available to you depend on the problem you face as well as the type of shortwave radio you are using. Here are suggestions for two shortwave models.
Satellite radio customers who lack a built-in satellite-ready stereo system may opt for an FM modulator. This device uses a series of technology products to convert satellite radio signals into standard FM transmission accessible to any radio.
A world band radio functions and looks just like a standard AM/FM radio, however it receives a different radio frequency. It is a shortwave radio that is capable of receiving signals from all over the world. This allows you to listen to stations from the United States no matter your location in the world.
If you are experiencing performance issues with your AM/FM radio, there are several options available to try and solve the issues. The specific methods for solving the problems depend on what type of problem you encounter and the model of radio with which you are working. Some methods, on the other hand, are pretty much the same no matter the model.
The Grundig model S350DL radio tunes into AM, FM and shortwave stations using a quick tuning knob and slow tuning knob. The S350DL is portable and features a carrying strap, an extendable antenna and a programmable clock. After setting up your Grundig, you might have questions about how to better tune stations, improve reception and boost sound quality. You'll want to be able to maximize the S350DL's performance before relying on it for news, weather or emergency updates.
Modern radios typically use both FM and AM signals, but they need two antennae to do so. AM antennas are responsible for picking up AM signals, which have unique characteristics and behave differently than their FM counterparts.
Racing radio communication refers to the communication between the driver and the crew chief during a race. The equipment used may vary depending on whether the racing team is involved in long track or short track racing.
A distributor of communication equipment, Mobile Radio Communications sells gear for use in off-road activities such as off-road racing, biking and paragliding. Mobile Radio Communication sells and provides customer service for a selection of military-grade equipment from quality manufacturers.
In two-way radio communication, ten-codes are numeric code words for frequently used messages, such as 10-4 or "OK." Law enforcement as well as Citizen's Band radio operators use ten-codes to communicate.
Cell phones have become a normal accessory in everyday life, providing assurance of communication wherever a person may be in his daily rounds. The cellular radio communication system is what keeps that communication possible.
Survivalists prepare themselves for emergency situations. A goal of survivalists is to be prepared to live in the event that the infrastructure collapses in an area. One aspect of this preparation is communication via radio.
Communication tools continue to evolve, making staying in touch with others easier. Mobile communication tools, like cell phones and wireless Internet, utilize cellular radio communication to function. Cellular radio communication relies on radio waves to operate.
Delta Modulation (DM) is an information processing system used to convert a signal into digital information. Because it is efficient and emulates a good degree of fidelity, it is often used to encode audio from a live source into a file your computer can read. Under certain circumstances, though, DM can fail to reproduce a good approximation of the source. These situations are called "distortion" and there are two primary kinds found in DM.
A directional coupler is a passive electronic device, whose basic function is to operate on an input signal and produce two output signals. This is typically done by employing two transmission lines in close proximity, such that the energy flowing through one is "coupled" to the other.
The primary purpose of a Grundig personal radio is to tune in to and listen to stations by way of a portable device. Upon receiving your radio, you may have some questions about how to tune in to stations. Following a few simple steps will have you listening to your desired radio stations in little time. You can prepare your device for tuning by turning up the volume and extending the antenna, activate auto tuning, tune stations in manually and save stations to one of 10 preset buttons.
FM tuners allow you to pick up broadcasts using frequency modulation, or FM, technology. FM technology allows radio receivers to pickup high-quality signals in local areas. FM tuners are not typically considered high-tech devices. Still, they have varied specifications, proving that not all tuners are the same.
The Grundig S350 personal radio is a portable device that receives FM and AM signals. Follow a few simple steps to operate your S350 efficiently. You can power your radio using an AC cord or batteries, adjust the radio's basic settings before use, turn the radio on with or without a timer and tune in your favorite stations.
It is difficult for consumers to choose which car radio product to use, given that the airwaves are abuzz with so many radio signals. Between analog and digital, satellite and HD, the choice can be daunting. Make an informed decision when you purchase your new radio.
Edwin Armstrong patented the first FM --- or frequency modulation --- radio in 1933. Today, FM tuners come in many different styles, but each works through the same combination of parts, allowing the system to function correctly. Although tuners might appear complicated, there are several specifications of a few basic parts that allow FM tuners to work.
Picking up AM and FM radio frequencies is the primary purpose of the Sangean ATS 505 portable radio. Upon receiving your device, you may have a few questions about its basic operation. Following a few simple steps will have you operating your device effectively and efficiently in little time. Learn to properly power your device with the AC adapter or batteries, set the time on the display, find stations with "Direct Tuning," locate stations with "Manual Tuning" and memorize and recall stations.
The first Frequency Modulation (FM) radio was patented by Edwin Howard Strong in December 1933. Today, as of 2010, FM receivers come in a variety of designs, shapes and sizes. Supporting these FM receivers is a system that contains integral parts in order for the receiver to function properly. These parts have various specifications on certain designs, but follow the same basic principle of receiving and processing the same modulated frequency.
Radio frequency refers to the rate of oscillation, or spinning, that corresponds to electrical signal frequencies used to produce radio waves. RF, or radio frequency, modulators take an input signal and modify the format of the resulting output signal.
Listening to music or speech-based programs on the radio is a pastime often enjoyed while driving, cooking or exercising. By identifying the knobs on a radio you can control the functions of the radio device to accommodate your needs. It is important know-how, so that you can tune the radio into a suitable station, turn the volume up or down or select another function of the stereo system, such as FM or AM, or switch to the CD mode.
A popular piece of technology for those living abroad, shortwave radios give users the ability to listen to radio broadcasts from around the world. Operating between the frequencies of 350 KHz and 30,000 KHz, shortwave radios capture radio signals as they rebound off the earth's ionosphere. And while you can't control the atmospheric conditions that dictate the strength of shortwave signals, there are a few things that you can do to improve shortwave reception on your Grundig S350.
The Crosley radio company was a Cincinnati, Ohio company. It was one of the first companies to see a market for an affordable radio receiver and began producing radios in 1920 with the $7 Harko Receiver. Crosley was one of the top radio producers through the 1950s.
Without wireless radio communication, the world would be without AM/FM/Satellite radio, walkie talkies, amateur radio and cell phones. Some forms of television work on the same principle as the various forms of radio; communicating without wires.
Knowing how to test your Sony Blu-ray player can prevent you from experiencing frustration and save you time. The model BDP S350 comes with a remote control, can be hooked up a multitude of different ways to your television and features a semiconductor laser system (utilized during playback). Make sure you verify that it's connected properly to your television, plugged in to a power source, functioning correctly with the remote control and that it's able to play a disc correctly.
Radio signals are a type of electromagnetic wave, and your FM (Frequency Modulation) car antenna is designed to intercept these waves on the same frequencies as the broadcast transmitter and turn them into high quality audio.
The radio has long been the constant companion of the daily commuter and the long-range motorist. Reception, however, is not always as consistent. With its weaker signal, AM listeners often find themselves trying to make out their favorite talk show or music through waves of static, especially when driving near tall buildings.
Analog radio signals cause characteristic changes, or modulations, in the radio waves that carry them: amplitude modulation (AM) and frequency modulation (FM). An old technology compared to newer digital signals such as satellite and high definition radio, differences that distinguish analog radio from digital radio include signal characteristics, sound clarity and cost.
An RF (radio frequency) coupler is a device used to control the direction and amplitude (extent) of RF signals. RF couplers come in a variety of types and are considered passive devices.
As Hybrid Digital (HD) radio technology becomes increasingly accessible and affordable to the general public, more listeners are deciding that it's time to upgrade. The benefits of owning an HD radio receiver are FM radio with near CD-quality sound; AM radio that sounds as clear as traditional FM; no static or fading signals; and transmission of additional helpful information, such as song titles and artists. If you live in Alabama, the number of HD radio stations is growing fast. As of 2010, 30 stations broadcast 52 HD radio channels throughout Alabama, with more coming soon.
Modulation alters properties of a waveform--called a carrier signal or wave. Digital modulation uses binary code to transfer a digital signal over an analog system such as a phone line, which is the case with a modem (modulator and demodulator creates a modem). Digital modulation is also helpful in music to create or alter sound waves.
Radio waves are short on history (discovered only a century ago), but they're long on use. They were first used early in the 20th century with the invention of the telegraph. During World War I, the military used radio waves in the form of radar to locate ships. By 1930, though, radio stations were broadcasting all over Europe and America and the radio receiver was a common household item. Today, the field of radio communications provides the global community with everything from microwave ovens to wireless computer networks.
Portable AM/FM radios are quickly becoming outdated with new satellite and car radios taking over the market, but that doesn't mean you have to settle for a lower quality of sound. There are a few tips for adjusting your radio and its antenna to ensure you are getting the best quality signal and sound out of your portable AM/FM radio.
Invented by Edwin Armstrong in the mid-1930s, the FM signal provided a significant improvement in audio quality over the earlier AM frequency. The U.S. military first put the improved signal to major use during operations in World War II. Today, most music stations broadcast in FM frequency, while the AM frequency is left to talk stations. FM receivers are ideal for music listeners, providing free music with high-quality sound.
The term radio, though frequently used to refer to the transmission of sound waves, actually has a broader definition. "Radio" applies to any signal transmission using electromagnetic waves, waves with frequencies below visible light waves--this includes pictures and other electronic data. Since its invention, radio has formed a principal means of mass communication, spreading news, opinions and propaganda to a great deal of individuals.
Of all the methods of communication, the FM radio is one of the most well-known forms of entertainment, news and music. But while this system of radio transmission eventually proved to be innovative and extremely popular, the early history of the FM radio and its inventor is a mostly tragic adventure.
Man has been using radio transmissions as a means of communication since 1895 when Guglielmo Marconi sent the first "wireless transmission." By 1920 radio broadcasting had become an entertainment medium as well as a communication medium. Over time the capabilities of radio broadcasting became divided between two radio frequencies: AM and FM.
The radio is pretty amazing, even today. We turn it on, and out comes sound, sound sent from miles and miles away. The radio is over a hundred years old and we were sitting around it listening to music and news long before the television was even dreamed up. After a hundred years of progress the radio hasn't changed much--it's still providing us with music nearly anywhere we go, just about 24/7, and it's still using good old radio waves.
The Panasonic RF-2200 is a personal AM/FM/shortwave radio that can be operated using batteries or an AC adapter. In shortwave mode, the RF-2200 can pick up eight different bands (frequency ranges). Shortwave radio signals travel far greater distances than AM or FM, enabling you to listen to international radio stations on your RF-2200.
Simple crystal radio sets may have started the history of radio, but it was the invention of the tube radio that jumpstarted it. Before tube radios, a single person could listen to a weak signal using an earphone; afterward, radio became a complete industry that provided entertainment and information for entire families. The reign of tube radio lasted from its inception in the early 1900s into the 1960s, when transistors finally replaced them.
The Grundig S350 is a radio manufactured by German consumer electronics company Grundig AG. California-based Eton Corporation sells this radio in the North American market. Although the radio retains the Grundig brand, it is sometimes sold as the Eton S350.
The discovery of a carrier for electronic signals in 1856 spawned the world of radio transmission waves. James Clerk Maxwell's mathematical theory of electromagnetic pulses being sent through the atmosphere were the basis for the development of transmitters and receivers for voice and music broadcasting. FM radio waves are a result of these efforts.
Radio waves and the easy transmission of information continues to revolutionize communication. Radio can seem like magic, like a box that picks information straight out of the air. In fact, there are actually energy waves that are being sent out and the radio receiver can pick them up. Personal radios can make these waves and send them out so others can pick them up.
Digital broadcasting, or DAB, is a new form of radio that is replacing traditional analog broadcasting frequencies. Television broadcasting and cell phones have already switched from analog to digital broadcasting and radio stations are not far behind. Police and other public-safety units use a mix of traditional analog and new digital equipment. Both systems have strengths and weaknesses that define the usefulness of each and show that sometimes a little bit of old is still beneficial when mixed with the new.
When purchasing a radio, consider which transmission type will suit you best. You may have to determine how good digital and analog services are at the location you intend to use the radio to ensure you make the right choice. If you like the appeal of an old-fashioned analog radio purely for its stylish aesthetics but would rather have the modern satellite transmission method, there are retro-styled digital radios available. It is worth considering that the United States is moving in favor of digital transmission, which may affect the long-term worth of analog models, as reported in PR Newswire Washington.
Although HD and high fidelity radio have been used interchangeably throughout the years, the two terms are actually used to define very two different concepts. Whereas one is an actual audio system, the latter is the ability of a certain system to reproduce audio sounds effectively.
Crosley makes modern and retro style radios with high-fidelity audio and minimal interfaces. Most Crosley radios have only three knobs and no additional buttons, so the controls are easy to learn. You can also set up the radios quickly by simply attaching the power cord and plugging them in.
Radio has been around for decades yet it is still a mysterious technology for many people. The majority of the population still does not have a firm understanding as to how radios function, much less what parts of a radio make it work.
We use radio waves to transmit audio, video and data information. But how exactly do we do this? What equipment is needed? How does the technology actually work?
Digital radio is when transmission and reception sound patterns are processed in numbers. Analog radios processes sound with electrical signals. Digital radios are becoming popular with consumers. Digital radios offers a clearer sound and a higher frequency. There is a wider selection of stations with digital radio. With digital radio, the listener can program it to receive a particular station of interest. Digital radio gives the convenience of extra stations without the fees attached. There are several different makes and models for digital radios.
Radio frequencies represent a subsection of electromagnetic energy found on the energy spectrum. Signal strength differentiates the different types of radio waves, and all radio waves fall between 1mm and 100km in distance, and 3 KHz to 300 GHz in frequency.
A shortwave radio is a receiver capable of getting transmissions from around the world on frequencies between 3 and 30 MHz. People use these radios for entertainment and to keep up with emergency situations. Radio Shack sells three shortwave radios at its stores, with prices ranging from economical to high-end expensive. The radios can be purchased in the store or online.
All kinds of simple AM radio circuits exist, but FM simple radio circuits have been limited during the transition from vacuum tubes to transistors. A simple one-transistor FM radio is the focal point of this article. It is based on some earlier designs of super-regenerative FM radios from the 1950s and 1960s. It is also available in a kit form with parts sources provided in the Reference section. A summary of low technology used on simpler FM radios is also covered.
Digital radio has become popular since the use of digital media players. iTunes and Windows Media Player have digital radio streams for FM broadcasts.
Introduced by Chevrolet (a GM brand) in 1957, the Wonder Bar radio was the first automatic "station-seeking" radio tuner of its kind. Drivers simply set the minimum desired signal strength. Once he pushed a button, the device would scan through the spectrum of AM/FM radio frequencies until it found the first sufficiently strong station.
Whether you feel you are having your privacy impeded upon or are afraid that potentially confidential information could be leaked from your home, you may want to find out if you are being electronically bugged. With today's technology it is very possible to be bugged without being aware of it, and sadly there are not any devices you can buy that are 100 percent accurate in letting you know if you are in fact bugged. However there is a method you can use yourself that will tell you if Big Brother is listening.
When a sound is first played, it is picked up by a microphone and translated into a sine wave that represents the sound. The carrier waves start out with no information inscribed in them until they are modified by the information from the electrical information from the microphone. These electromagnetic waves are more effective than mechanical waves, because electrical waves can travel in a vacuum while mechanical waves need a medium to travel in. Electromagnetic waves travel at the speed of light, which is faster than the mechanical waves that travel at the speed of sound.
The Hallicrafters Company produced some of the most desirable amateur communication radios of the 1930s, '40s and '50s. Hallicrafters produced the classic SX-28, SX-42 and SX-101 communication receivers, and the HT-1 and HT-32 transmitter line. This equipment is still in use today and very popular with antique radio collectors.
FM radio, one of the cultural explosion elements of the 1960s, came into its prominence in the 1970s. FM stands for frequency modulation, which described how the signal you receive in your radio is sent to your radio and translated into the sounds you listen to. The FM transmitter generates what's known as a carrier wave, which is a constantly transmitted signal FM radios are designed to seek. The carrier wave, when the baseband signal is added to it, modulates (changes) the frequency of the carrier wave to the frequency licensed to the station. This is also the way FM…
Radio communication is among the easiest forms of communication to produce and can be the most useful method of communication in times of area-wide trouble. The phenomenon has been with us for almost a century and it is still widely used for entertainment and other useful things today.
Radio communication is the process by which radio signals are produced, processed, and then transmitted to a radio unit. Radio communication derives its roots from the telegraph machine, when in 1887 Heinrich Hertz discovered the process of transmitting electromagnetic signals through the atmosphere. The process was eventually patented by Guglielmo Marconi in 1895.
Communication using radio waves has been possible and popular since Guglielmo Marconi's invention of the first practical radio transmitter and receiver in 1895. Although in many ways, radio transmissions appear to be fading in popularity as more people switch to satellite and cable television and to satellite based radio, the reality is that all of those technologies use and are based on radio communication.
Do you like to look for lost treasures? If so, a metal detector will do! However, don't break your wallet by purchasing a high end metal detector. Learn how you can now make your own homemade metal detector!
The purpose of a radio frequency (RF) modulator is to manipulate information encoded onto a carrier wave. Many of our technological gadgets--like video cameras, radios, and televisions--can actually emit energy pulses. An RF modulator can change those pulses into information and how we hear or see them just depends on whatever device we use. There are variants of this device, which manipulate stronger or more complicated digital signals for larger applications, but the basic principles are always the same. They take in energy pulses and transform them. To understand the purpose of an RF modulator, it's necessary to learn a…
In order to understand the particulars of FM radio, we must start with the basic science behind radio technology. Radio waves are capable of transmitting more than just sound. They are the basis for all modern wireless technology, including cell phones and wireless Internet. A radio works by converting data (of any kind) into a sine wave. A sine wave is an electronic signal based on oscillating (changing between two points) electrical current. The sine wave moves repeatedly between two points of high and low voltage, and this change is known as the wave's amplitude. These electrical currents will naturally…
Both AM and FM radio use electromagnetic radiation to broadcast sound information. Radio transmitters produce what is known as a carrier signal. A carrier signal is a high frequency signal on a certain frequency which carries the sound information in it. When a radio signal is picked up by a receiver, it looks for small changes in the carrier wave. These changes are turned into the sound information. The listener doesn't hear the actual radio signal, but the information encoded in it.
All sound energy is in the form of a wave. The frequency of a wave is the measurement of the number of cycles that it undergoes in a given time frame. Hertz is a measurement of frequency that depicts the number of wave cycles per second. FM signals are measured in megahertz so an FM signal of 97.5 relates to 97,500,000 waves/second.
Radio began the communication revolution. Unlike telegraphy, which linked two specially trained operators, or telephony, which linked only two speakers, radio had the potential to link millions to information, entertainment and public affairs. Broadcasting consists of changing electromagnetic waves with frequencies below those of visible light in two ways: modulation and amplification. Modulation allows the manipulation of waves so that a receiver "hears" different frequencies in succession, which register as different sounds to the human ear. Amplification increases the range of sound that can be transmitted. The first radio microphones were large electromagnets that transformed sound waves into electromagnetic waves.…
Although the mechanics behind HD radios are certainly similar to that in traditional analog radio systems, it is the quality of the sound that is different. In HD radio, FM radio sounds as good as a CD player, while AM radio is upgraded to FM-quality in a traditional radio. No static, crackling or fading is present. Additionally, more transmission of information is possible, as are many luxury features that make the radio more of an interactive listening station than an old-fashioned radio.
Digital radio varies from traditional radio because it has information encoded differently on its carrier waves. Amplitude modulation (AM) or frequency modulation (FM) radio tends to be dramatically weaker than digital signals. Both AM and FM tend to read at kilohertz or megahertz, rather than gigahertz, as is the case with many digital radios. Analog signals tend to have trouble differentiating between undesired and desired signals. This also means that someone with a traditional radio that uses an analog method of transmitting information will get a lot more static than a digital radio signal.
Radio was the first invention in a revolution that has made it possible for anyone in the world to communicate with anyone else. The definition of a theory of electromagnetism by James Maxwell and experiments at the beginning of the twentieth century by Hertz, Tesla and Marconi led to the development of systems to broadcast signals in the air rather than over wires. Unlike telegraphy, which linked two specially trained operators, or telephony, which linked only two speakers, radio had the potential to link millions to information, entertainment and public affairs through broadcast technology.
