Objective: The objective of this lab is to design and AM Radio.
Introduction: Am radio uses Amplitude Modulation (AM), which works by varying the strength of the transmitted signal in relation to the information being sent. When you tune into an AM radio station, for example 1560 on the AM dial the transmitter’s sine wave is transmitted the data at 1560,000 hertz. What this number essentially means is that the sine wave repeats every 1560,000 times per second. The data is modulated onto the carrier wave by changing the amplitude of this sine wave. The radio station uses and amplifier in order to amplify the signal. For large AM stations the signal is amplified to about 50,000 watts. After the signal has been amplified the radio station sends the radio waves out into space with the help of an antenna. This is essentially how data gets transmitted from an AM station onto a radio receiver. Now let’s take at the inner working of an AM receiver and required steps in order to take that signal from the air and into a speaker.
Provided below is a block diagram of an AM receiver.
Antenna: The purpose of the antenna is to capture the radio signal from the air waves and into the tuner. An AM antenna is simply a wire or a metal stick.
Tuner: The antenna will pick up many signals. The function of the tuner is to separate obtain the specific signal you need and ignore the others. For example, if you are tuned into AM 1560, we want the tuner to isolate every other signal and recover this signal. An AM tuner works on the principle called resonance. What this means is that an AM tuner resonate & amplify at certain frequency and avoids all the other frequencies.
RF Amplifier: The reason we incorporate an RF amplifier into the AM receiver is because an RF Amplifier helps us further improve the signal. The major benefits of using RF amplification are the following:
1. Improved image frequency rejection
2. More gain and thus better sensitivity
3. Improved noise characteristics.
Detector: Once the data has been obtained, we have to extract the voice out of that sine wave. This is where the detector comes into play. For an AM radio, a detector is made from a diode.
Has anyone ever wondered how radio communications changed society during the 1930’s? According to the research done by the Education Foundation, many people believe that the most important development in the radio at that time was entertainment; this is entirely false. In fact, radio communications not only made an impact in the way people received their news, but also brought together a nation that got out of a brutal depression. Together, the nations as one made radio communications the commanding form of media in the 1930’s. As stations and businesses were beginning to establish themselves, companies from across the nation were taking notice in the department of advertisement. This new realm ignited a spark for the nation’s new economy which later boomed and gave rise to an economically and socially powerful country.
Most radio historians assert that radio broadcasting began in 1920 with the historic broadcast of KDKA. During the 1920s radio benefited Americans because it was a source of their entertainment, the music industry of jazz, and advertisements.
Radios in the book show power in many different forms, whether it be propaganda, the ability to know of the outside world or just owning a radio, sets one higher than those without.
Rogers Communication started with a vision that "radio is an electric pipeline" by Edward S. Rogers, Sr. In 1925 Mr. Rogers, Sr. invented the world's first alternating "current (AC) radio tube."1 The radio tube was a huge break through in communication technology and in radio reception, and as a result of the invention; radios became common medium of communication.
However, satellite radio is banking on a commercial free format to steal listeners away from terrestrial radio. Sirius offers 65 commercial free channels of music and 55 news, sports and talk stations. And the one thing that satellite has over its less lofty competitor is that you can’t loose the signal as you drive across America. The two major competitors for the satellite radio listeners are Sirius and XM.
These target groups spend an extraordinary amount of time listening to radio, especially in the car, and should be extremely receptive to the XM product due to their constant need for radio entertainment and willingness to pay for it.
The radio was the first device to institute mass communication and when first brought to the American people, it did just that. Since 1920, when KDKA, the first officially government licensed radio station began,2 Americans began to use the radio to help interpret the economic unrest around them, confusing political issues, and on the whole a newly forming American culture.3 Radio gave the American people control of their own lives on a more familiar and personal level, while still allowing them to feel connected to others all across the nation. The radio meant mass communication, a mass audience, and a new and better kind of understanding in the otherwise confusing culture of America at the time.4 The American people responded well to the device for these reasons alone and by 1930, radio sales grew tremendously to 13.5 million from the previous 75,000 of 1921.5 The radio was able to provide the American people a sense of togetherness during an otherwise alienated and estranged time.
Traditional AM/FM Radio. Sirius’s competition also includes traditional AM/FM radio. Unlike SIRIUS radio, traditional AM/FM radio has had a well established market for its services for many years and generally offers free broadcast reception paid for by commercial advertising rather than by a subscription fee. Also, many radio stations offer information programming of a local nature, such as local news and sports, which Sirius does not offer as effectively as local radio. Some radio stations also have begun reducing the number of commercials per hour, expanding the range of music played on the air and experimenting with new formats in order to compete more directly with satellite radio services.
Many inventions have impacted the world throughout history but in my opinion one of the most impactful one’s was the invention of the radio . This invention provided society with many things which include entertainment, communication, and easier access to information. Radio is still a central part of the society today but just like any other invention radio has an interesting history of how it progressed through time.
Cell phones use radio frequencies to transmit signals. Radio Frequencies (RF) are a form of electrical waves similar to those used in radios, microwaves, radars or satellite stations. They are emitted from a transmitter, and received using an antenna. This telephony technology is restricted geographically to small zones called “Cells”. Every cell has a base station capable of sending and receiving radio waves. When a call is started a signal leaves the handheld unit headed to the closest base station. This station answers by allocating a specific channel to the unit. When this “channel” is established, modulated radio frequency signals are both received and transmitted. The head of the user is in the near field of use because the distance from the antenna to the head is a few centimeters. (Blettner & Berg 2000) If the antenna is inside the body of the phone, the exposure to Radio Frequencies is greater. The antenna might be requesting a stronger signal to contest with the interference of the battery or the actual shell of the phone’s body.
Analog communication employs continuous transmission of an electromagnetic wave form that varies in frequency and amplitude.
Frequency modulation is, of course, used on the FM band. And it is used for
A cell phone is essentially a two-way radio consisting of a radio transmitter and a radio receiver. When you talk to your friend on your mobile phone, your mobile transfers your voice into an electrical signal, which is then transmitted through radio waves to the nearest cell tower. The network of cell phone towers then replays the radio wave to friend’s cell phone, which converts it to an electrical signal and back to sound. Cell phones transmit radio waves in all directions.
call sign, not just the radio frequency), an option to scan through channels searching only for stations playing a specified music genre, and of course adjustable treble and bass, which I'll never touch. The car manual, which had more pages dedicated to the stereo than the rest of the automobile, revealed a clever feature where I can program a volume for the radio to reset...
Radio broadcasting was introduced to the public in the early 1920s (Potter 226). There was only one type of broadcast protocol in the 1920’s and 30’s being AM radio(The Early Years). In 1921 there were only five AM radio stations, and only about 1% of all households in this country had a receiver (Potter 226). A receiver was basically another name for a radio because at this time radios were very expensive and there were not enough radio stations to make the system work. However, in 1923 there were over 500 stations to pop up which in turn led to increased sales of receivers to the general public (Potter 226). With the popping up of more radio stations the more receivers were being bought which meant that many people in the public were tuning into these various radio stations for information and entertainment. Radio was on the rise and it seemed that there was nothing slowing it down.