Radio is a technology used to deliver signals by modulation and electromagnetic radiation (electromagnetic waves). And propagate the wave passing through the air and can also propagate through the vacuum of space, because these waves do not require a carrier medium (such as air molecules).
The development of the technology now to impact the world of radio broadcasting. First we can only enjoy radio broadcasts with the wave AM (amplitude modulation). However, now the audience was spoiled by the emergence of FM radio waves (frequency modulation) to speak out more clearly. The person credited with finding the FM wave is Edwin Howard Armstrong, known as the "father of the inventor of FM radio".
Armstrong, a technical expert radio inventor who was born on December 18, 1890 in New York City, United States (U.S.). Cleverness and tenacity have appeared since childhood. In fact, when he was only stepping 14 years, he has aspired to become an inventor. The moment when he was a teenager, he began trying to become a service person household tools cordless (wireless), and when it was in high school, he has began a trial by making the antenna mast in front of his house to learn about wireless technology that when It is often impaired. He was quickly able to understand the issues in these communication tools. He also can find a weakness on the receiving end of transmission signal communication. In fact, there is no other way to strengthen the power at the sending end.
To develop the knowledge in the field of communication waves, after graduating high school, Armstrong entered Columbia University majoring in engineering. At the university that he continued his research in the wireless field. In the third year at Columbia University, Armstrong introduces its findings, a first radio wave amplifier (radio amplifier). Radio itself has actually been discovered in advance by using Lee De Forest Audion tube tube named Lee De Forest. However, the waves it emits are still too weak.
Armstrong studied the workings of Lee DeForest tube and then redesign by taking the electromagnetic waves coming from a radio transmission and quickly gave the signal back through the tube. Just a moment, the signal strength will increase as much as 20,000 times per second. This phenomenon is by Armstrong called the "regeneration of the radio", which is an important and necessary discovery when the radio is the first time there. With this development, the radio technician no longer needed 20 tons of generators so that their radio station on the air. Design a single circuit Armstrong became the key findings of the continuity of the wave transmitter became operational core of the radio. And he graduated bachelor of engineering in 1913. Above findings, the Armstrong patented his creation and give license to the Marconi Corporation in 1914.
Six years later, Armstrong Westinghouse bought the patent for the superheterodyne receiver, and start their work became the first radio station KDKA in Pittsburgh named. Begin radio became very popular at the time, ranging from entertainment to important news, no one not wearing a radio service. After that, keep popping up other radio waves. RCA (The Radio Corporation of America) immediately purchase all radio patents as well go buy another radio.
After World War I ended, Armstrong returned to Columbia University and worked as a professor at the university. In 1923 he married Marion MacInnes, secretary of the President of RCA, David Sarnoff. In that decade he was involved in a corporate war to control radio patents. This continued until early 1930, and Armstrong lost in court. Nevertheless, he continued research to solve statistical problems radio. He concluded, there is only one solution so that his work was stolen can be appreciated, ie designing an entirely new system.
Various studies also continue to do to further refine her voice radio. In 1933 Armstrong introduced FM radio (frequency modulation), which provides clear reception even though there was a storm and offering high sound accuracy not previously exist. The system also provides a single wave brought two radio programs with a single haul. The development is called multiplexing.
Regarding the difference between AM and FM waves, can be explained as follows. Terpancarkan voice signals can not be directly due to signal noise rather than electromagnetic waves. If the voice signal is converted into electromagnetic waves though, how long the antenna is needed. To be able to transmit sound signals more easily, the sound signal is superimposed on the first radio signal with a higher frequency of the sound signal. The method for laying the voice signal on a radio signal is called modulation. Modulation is often used radio amplitude modulation (AM - amplitude modulation) and frequency modulation (FM - frequency modulation)
The main difference between the wave AM with FM is a way to modulate his voice. FM waves have an additional range of plus 455 KHz. So, if there frekeensi 88.00 FM radio, in fact he uses the frequency of 88.00 MHz + 455 KHz. Why is there an additional 455 KHz? Well, it modulates the FM waves of sound digitally. So, it enumerated the sound waves in digital audio corresponding audio frequency (ear threshold between 6 Hz - 20 KHz). After digitally chopped (optional 455 KHz earlier, as a digital audio buffer), digital signal TSB. mixed in with the radio wave (carrier) frequency of 88.0 MHz before, and then thrown into the open air. Important this part of the FM transmitter system is the antenna, transmission line, and the transmitter itself.
To introduce the findings at the world, in 1940, Armstrong received permission to establish the first FM radio station established in Alpine, New Jersey. Thanks to these findings, in 1941, the Franklin Institute has honored Armstrong Franklin Medal, which is one of the highest honors the scientific community. His defeat in a dispute over the years with companies that have made use of the copyright, does not affect the provision of the Franklin medal.
But it was very unfortunate, Armstrong had to end his life with tragic way. The inventor of FM radio waves was found dead of suicide in 1954. His wife, Marion MacInnes, who became heir to the findings of Armstrong's continued struggle of her husband fought in court and won millions of dollars. Clarity over the sound it produces in the early '60s, dominating the FM channel radio system, and even used for communication between Earth and outer space by the U.S. National Space Agency, NASA.
