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The year 1913 in radio involved some significant events.
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The year 1913 in radio involved some significant events.
Edwin Howard Armstrong was an American electrical engineer and inventor, who developed FM radio and the superheterodyne receiver system.
Sir John Ambrose Fleming FRS was an English electrical engineer and physicist who invented the first thermionic valve or vacuum tube, designed the radio transmitter with which the first transatlantic radio transmission was made, and also established the right-hand rule used in physics.
The early history of radio is the history of technology that produces and uses radio instruments that use radio waves. Within the timeline of radio, many people contributed theory and inventions in what became radio. Radio development began as "wireless telegraphy". Later radio history increasingly involves matters of broadcasting.
A triode is an electronic amplifying vacuum tube consisting of three electrodes inside an evacuated glass envelope: a heated filament or cathode, a grid, and a plate (anode). Developed from Lee De Forest's 1906 Audion, a partial vacuum tube that added a grid electrode to the thermionic diode, the triode was the first practical electronic amplifier and the ancestor of other types of vacuum tubes such as the tetrode and pentode. Its invention helped make amplified radio technology and long-distance telephony possible. Triodes were widely used in consumer electronics devices such as radios and televisions until the 1970s, when transistors replaced them. Today, their main remaining use is in high-power RF amplifiers in radio transmitters and industrial RF heating devices. In recent years there has been a resurgence in demand for low power triodes due to renewed interest in tube-type audio systems by audiophiles who prefer the sound of tube-based electronics.
Lee de Forest was an American inventor and a fundamentally important early pioneer in electronics. He invented the first practical electronic amplifier, the three-element "Audion" triode vacuum tube in 1906. 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.
The coherer was a primitive form of radio signal detector used in the first radio receivers during the wireless telegraphy era at the beginning of the 20th century. Its use in radio was based on the 1890 findings of French physicist Édouard Branly and adapted by other physicists and inventors over the next ten years. The device consists of a tube or capsule containing two electrodes spaced a small distance apart with loose metal filings in the space between. When a radio frequency signal is applied to the device, the metal particles would cling together or "cohere", reducing the initial high resistance of the device, thereby allowing a much greater direct current to flow through it. In a receiver, the current would activate a bell, or a Morse paper tape recorder to make a record of the received signal. The metal filings in the coherer remained conductive after the signal (pulse) ended so that the coherer had to be "decohered" by tapping it with a clapper actuated by an electromagnet, each time a signal was received, thereby restoring the coherer to its original state. Coherers remained in widespread use until about 1907, when they were replaced by more sensitive electrolytic and crystal detectors.
The Audion was an electronic detecting or amplifying vacuum tube invented by American electrical engineer Lee de Forest as a diode in 1906. Improved, it was patented as the first triode in 1908, consisting of an evacuated glass tube containing three electrodes: a heated filament, a grid, and a plate. It is important in the history of technology because it was the first widely used electronic device which could amplify. A low power signal at the grid could control much more power in the plate circuit.
A regenerative circuit is an amplifier circuit that employs positive feedback. Some of the output of the amplifying device is applied back to its input to add to the input signal, increasing the amplification. One example is the Schmitt trigger, but the most common use of the term is in RF amplifiers, and especially regenerative receivers, to greatly increase the gain of a single amplifier stage.
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 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.
Valdemar Poulsen was a Danish engineer who developed a magnetic wire recorder called the telegraphone in 1898. He also made significant contributions to early radio technology, including the first continuous wave radio transmitter, the Poulsen arc, which was used for a majority of the earliest audio radio transmissions, before being supplanted by the development of vacuum-tube transmitters.
The Armstrong oscillator is an electronic oscillator circuit which uses an inductor and capacitor to generate an oscillation. The Meissner patent from 1913 describes a device for generating electrical vibrations, a radio transmitter used for On–off keying. Edwin Armstrong presented in 1915 some recent developments in the Audion receiver. His circuits improved radio frequency reception. Meissner used a Lieben-Reisz-Strauss tube, Armstrong used a de Forest Audion tube. Both circuits are sometimes called a tickler oscillator because the distinguishing feature is that the feedback signal needed to produce oscillations is magnetically coupled into the tank inductor by a "tickler coil" (L2, right). Assuming the coupling is weak but sufficient to sustain oscillation, the oscillation frequency f is determined primarily by the LC circuit and is approximately given by
John Stone Stone was an American mathematician, physicist and inventor. He initially worked in telephone research, followed by influential work developing early radio technology, where he was especially known for improvements in tuning. Despite his often advanced designs, the Stone Telegraph and Telephone Company failed in 1908, and he spent the remainder of his career as an engineering consultant.
The invention of radio communication was preceded by many decades of establishing theoretical underpinnings, discovery and experimental investigation of radio waves, and engineering and technical developments related to their transmission and detection. These developments allowed Guglielmo Marconi to turn radio waves into a wireless communication system.
The timeline of radio lists within the history of radio, the technology and events that produced instruments that use radio waves and activities that people undertook. Later, the history is dominated by programming and contents, which is closer to general history.
The Fleming valve, also called the Fleming oscillation valve, was a thermionic valve or vacuum tube invented in 1904 by English physicist John Ambrose Fleming as a detector for early radio receivers used in electromagnetic wireless telegraphy. It was the first practical vacuum tube and the first thermionic diode, a vacuum tube whose purpose is to conduct current in one direction and block current flowing in the opposite direction. The thermionic diode was later widely used as a rectifier — a device that converts alternating current (AC) into direct current (DC) — in the power supplies of a wide range of electronic devices, until beginning to be replaced by the selenium rectifier in the early 1930s and almost completely replaced by the semiconductor diode in the 1960s. The Fleming valve was the forerunner of all vacuum tubes, which dominated electronics for 50 years. The IEEE has described it as "one of the most important developments in the history of electronics", and it is on the List of IEEE Milestones for electrical engineering.
Roy Alexander Weagant was a noted Canadian-American radio pioneer.
Harry Shoemaker was an American inventor and pioneer radio engineer, who received more than 40 U.S. patents in the radio field from 1901 to 1905. His transmitter and receiver designs set the standard for the U. S. commercial radio industry up to World War One.
Captain Henry Joseph Round was an English engineer and one of the early pioneers of radio. He was the first to report the observation of electroluminescence from a solid state diode, leading to the discovery of the light-emitting diode. He was a personal assistant to Guglielmo Marconi.
Henry Harrison Chase Dunwoody was an American army officer, businessman, and inventor. Known in his own time for his work with the Army's Weather Bureau, he invented the carborundum radio detector in 1906. It was the first practical mineral radio wave detector and the first commercial semiconductor device.
The Marconi Wireless Telegraph Company of America was incorporated in 1899. It was established as a subsidiary of the British Marconi Company and held the U.S. and Cuban rights to Guglielmo Marconi's radio patents. American Marconi initially primarily operated high-powered land and transatlantic shipboard stations. In 1912, it acquired the extensive assets of the bankrupt United Wireless Telegraph Company, becoming the dominant radio communications provider in the United States.
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