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56-563: The two-way type of radio network shares many of the same technologies and components as the broadcast-type radio network but is generally set up with fixed broadcast points ( transmitters ) with co-located receivers and mobile receivers/transmitters or transceivers . In this way both the fixed and mobile radio units can communicate with each other over broad geographic regions ranging in size from small single cities to entire states/provinces or countries. There are many ways in which multiple fixed transmit/receive sites can be interconnected to achieve

112-460: A broadcast transmitter , a transmitter used in broadcasting , as in FM radio transmitter or television transmitter . This usage typically includes both the transmitter proper, the antenna, and often the building it is housed in. A transmitter can be a separate piece of electronic equipment, or an electrical circuit within another electronic device. A transmitter and a receiver combined in one unit

168-472: A frequency modulation (FM) transmitter, it is added by varying the radio signal's frequency slightly. Many other types of modulation are also used. The radio signal from the transmitter is applied to the antenna , which radiates the energy as radio waves. The antenna may be enclosed inside the case or attached to the outside of the transmitter, as in portable devices such as cell phones, walkie-talkies, and garage door openers . In more powerful transmitters,

224-432: A mass-production basis, which limited them to a number of specialised applications. The MOSFET was invented at Bell Labs between 1955 and 1960. It was the first truly compact transistor that could be miniaturised and mass-produced for a wide range of uses. Its advantages include high scalability , affordability, low power consumption, and high density . It revolutionized the electronics industry , becoming

280-429: A radio frequency signal which when applied to the antenna produces the radio waves, called the carrier signal . It combines the carrier with the modulation signal, a process called modulation . The information can be added to the carrier in several different ways, in different types of transmitters. In an amplitude modulation (AM) transmitter, the information is added to the radio signal by varying its amplitude . In

336-823: A radio transmitter or just transmitter (often abbreviated as XMTR or TX in technical documents) is an electronic device which produces radio waves with an antenna with the purpose of signal transmission up to a radio receiver . The transmitter itself generates a radio frequency alternating current , which is applied to the antenna . When excited by this alternating current, the antenna radiates radio waves. Transmitters are necessary component parts of all electronic devices that communicate by radio , such as radio (audio) and television broadcasting stations, cell phones , walkie-talkies , wireless computer networks , Bluetooth enabled devices, garage door openers , two-way radios in aircraft, ships, spacecraft, radar sets and navigational beacons. The term transmitter

392-434: A concept called trunking is commonly used to achieve better efficiency of radio spectrum use and provide very wide-ranging coverage with no switching of channels required by the mobile radio user as it roams throughout the system coverage. Trunking of two-way radio is identical to the concept used for cellular phone systems where each fixed and mobile radio is specifically identified to the system controller and its operation

448-518: A high voltage spark between two conductors. Beginning in 1895, Guglielmo Marconi developed the first practical radio communication systems using these transmitters, and radio began to be used commercially around 1900. Spark transmitters could not transmit audio (sound) and instead transmitted information by radiotelegraphy : the operator tapped on a telegraph key which turned the transmitter on-and-off to produce radio wave pulses spelling out text messages in telegraphic code, usually Morse code . At

504-566: A mix of the two types. Analog circuits are becoming less common, as many of their functions are being digitized. Analog circuits use a continuous range of voltage or current for signal processing, as opposed to the discrete levels used in digital circuits. Analog circuits were common throughout an electronic device in the early years in devices such as radio receivers and transmitters. Analog electronic computers were valuable for solving problems with continuous variables until digital processing advanced. As semiconductor technology developed, many of

560-540: A physical space, although in more recent years the trend has been towards electronics lab simulation software , such as CircuitLogix , Multisim , and PSpice . Today's electronics engineers have the ability to design circuits using premanufactured building blocks such as power supplies , semiconductors (i.e. semiconductor devices, such as transistors), and integrated circuits. Electronic design automation software programs include schematic capture programs and printed circuit board design programs. Popular names in

616-413: A radio wave. A radio transmitter is an electronic circuit which transforms electric power from a power source, a battery or mains power, into a radio frequency alternating current to apply to the antenna, and the antenna radiates the energy from this current as radio waves. The transmitter also encodes information such as an audio or video signal into the radio frequency current to be carried by

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672-586: A variety of license classes depending on use such as broadcast , marine radio , Airband , Amateur and are restricted to certain frequencies and power levels. A body called the International Telecommunication Union (ITU) allocates the frequency bands in the radio spectrum to various classes of users. In some classes, each transmitter is given a unique call sign consisting of a string of letters and numbers which must be used as an identifier in transmissions. The operator of

728-600: A variety of networks. Radio networks rose rapidly with the growth of regular broadcasting of radio to home listeners in the 1920s. This growth took various paths in different places. In Britain the BBC was developed with public funding , in the form of a broadcast receiver license , and a broadcasting monopoly in its early decades. In contrast, in the United States various competing commercial broadcasting networks arose funded by advertising revenue. In that instance,

784-425: Is called a transceiver . The purpose of most transmitters is radio communication of information over a distance. The information is provided to the transmitter in the form of an electronic signal called the modulation signal, such as an audio (sound) signal from a microphone, a video (TV) signal from a video camera, or in wireless networking devices, a digital signal from a computer. The transmitter generates

840-548: Is defined as unwanted disturbances superposed on a useful signal that tend to obscure its information content. Noise is not the same as signal distortion caused by a circuit. Noise is associated with all electronic circuits. Noise may be electromagnetically or thermally generated, which can be decreased by lowering the operating temperature of the circuit. Other types of noise, such as shot noise cannot be removed as they are due to limitations in physical properties. Many different methods of connecting components have been used over

896-406: Is it can often transmit more information ( data rate ) in a given bandwidth than analog, using data compression algorithms. Other advantages of digital transmission are increased noise immunity , and greater flexibility and processing power of digital signal processing integrated circuits . Electronics Electronics is a scientific and engineering discipline that studies and applies

952-540: Is switched by the controller. The broadcast type of radio network is a network system which distributes programming to multiple stations simultaneously, or slightly delayed, for the purpose of extending total coverage beyond the limits of a single broadcast signal. The resulting expanded audience for radio programming or information essentially applies the benefits of mass-production to the broadcasting enterprise. A radio network has two sales departments, one to package and sell programs to radio stations, and one to sell

1008-595: Is the voltage comparator which receives a continuous range of voltage but only outputs one of two levels as in a digital circuit. Similarly, an overdriven transistor amplifier can take on the characteristics of a controlled switch , having essentially two levels of output. Analog circuits are still widely used for signal amplification, such as in the entertainment industry, and conditioning signals from analog sensors, such as in industrial measurement and control. Digital circuits are electric circuits based on discrete voltage levels. Digital circuits use Boolean algebra and are

1064-448: Is therefore the process of defining and developing complex electronic devices to satisfy specified requirements of the user. Due to the complex nature of electronics theory, laboratory experimentation is an important part of the development of electronic devices. These experiments are used to test or verify the engineer's design and detect errors. Historically, electronics labs have consisted of electronics devices and equipment located in

1120-411: Is usually limited to equipment that generates radio waves for communication purposes; or radiolocation , such as radar and navigational transmitters. Generators of radio waves for heating or industrial purposes, such as microwave ovens or diathermy equipment, are not usually called transmitters, even though they often have similar circuits. The term is popularly used more specifically to refer to

1176-624: The IBM 608 was the first IBM product to use transistor circuits without any vacuum tubes and is believed to be the first all-transistorized calculator to be manufactured for the commercial market. The 608 contained more than 3,000 germanium transistors. Thomas J. Watson Jr. ordered all future IBM products to use transistors in their design. From that time on transistors were almost exclusively used for computer logic circuits and peripheral devices. However, early junction transistors were relatively bulky devices that were difficult to manufacture on

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1232-640: The UHF and microwave ranges, using new active devices such as the magnetron , klystron , and traveling wave tube . The invention of the transistor allowed the development in the 1960s of small portable transmitters such as wireless microphones , garage door openers and walkie-talkies . The development of the integrated circuit (IC) in the 1970s made possible the current proliferation of wireless devices , such as cell phones and Wi-Fi networks, in which integrated digital transmitters and receivers ( wireless modems ) in portable devices operate automatically, in

1288-685: The 1920s. All these early technologies were replaced by vacuum tube transmitters in the 1920s, which used the feedback oscillator invented by Edwin Armstrong and Alexander Meissner around 1912, based on the Audion ( triode ) vacuum tube invented by Lee De Forest in 1906. Vacuum tube transmitters were inexpensive and produced continuous waves , and could be easily modulated to transmit audio (sound) using amplitude modulation (AM). This made AM radio broadcasting possible, which began in about 1920. Practical frequency modulation (FM) transmission

1344-448: The 1960s, U.S. manufacturers were unable to compete with Japanese companies such as Sony and Hitachi who could produce high-quality goods at lower prices. By the 1980s, however, U.S. manufacturers became the world leaders in semiconductor development and assembly. However, during the 1990s and subsequently, the industry shifted overwhelmingly to East Asia (a process begun with the initial movement of microchip mass-production there in

1400-538: The 1970s), as plentiful, cheap labor, and increasing technological sophistication, became widely available there. Over three decades, the United States' global share of semiconductor manufacturing capacity fell, from 37% in 1990, to 12% in 2022. America's pre-eminent semiconductor manufacturer, Intel Corporation , fell far behind its subcontractor Taiwan Semiconductor Manufacturing Company (TSMC) in manufacturing technology. By that time, Taiwan had become

1456-712: The EDA software world are NI Multisim, Cadence ( ORCAD ), EAGLE PCB and Schematic, Mentor (PADS PCB and LOGIC Schematic), Altium (Protel), LabCentre Electronics (Proteus), gEDA , KiCad and many others. Heat generated by electronic circuitry must be dissipated to prevent immediate failure and improve long term reliability. Heat dissipation is mostly achieved by passive conduction/convection. Means to achieve greater dissipation include heat sinks and fans for air cooling, and other forms of computer cooling such as water cooling . These techniques use convection , conduction , and radiation of heat energy . Electronic noise

1512-563: The US, these fall under Part 15 of the Federal Communications Commission (FCC) regulations. Although they can be operated without a license, these devices still generally must be type-approved before sale. The first primitive radio transmitters (called spark gap transmitters ) were built by German physicist Heinrich Hertz in 1887 during his pioneering investigations of radio waves. These generated radio waves by

1568-610: The antenna may be located on top of a building or on a separate tower, and connected to the transmitter by a feed line , that is a transmission line . Electromagnetic waves are radiated by electric charges when they are accelerated . Radio waves , electromagnetic waves of radio frequency , are generated by time-varying electric currents , consisting of electrons flowing through a metal conductor called an antenna which are changing their velocity and thus accelerating. An alternating current flowing back and forth in an antenna will create an oscillating magnetic field around

1624-508: The audience of those programs to advertisers. Most radio networks also produce much of their programming. Originally, radio networks owned some or all of the stations that broadcast the network's radio format programming. Presently however, there are many networks that do not own any stations and only produce and/or distribute programming. Similarly station ownership does not always indicate network affiliation. A company might own stations in several different markets and purchase programming from

1680-461: The background, to exchange data with wireless networks . The need to conserve bandwidth in the increasingly congested radio spectrum is driving the development of new types of transmitters such as spread spectrum , trunked radio systems and cognitive radio . A related trend has been an ongoing transition from analog to digital radio transmission methods. Digital modulation can have greater spectral efficiency than analog modulation ; that

1736-409: The basis of all digital computers and microprocessor devices. They range from simple logic gates to large integrated circuits, employing millions of such gates. Digital circuits use a binary system with two voltage levels labelled "0" and "1" to indicated logical status. Often logic "0" will be a lower voltage and referred to as "Low" while logic "1" is referred to as "High". However, some systems use

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1792-459: The circuit, thus slowing the computer. The invention of the integrated circuit by Jack Kilby and Robert Noyce solved this problem by making all the components and the chip out of the same block (monolith) of semiconductor material. The circuits could be made smaller, and the manufacturing process could be automated. This led to the idea of integrating all components on a single-crystal silicon wafer, which led to small-scale integration (SSI) in

1848-419: The conductor. The alternating voltage will also charge the ends of the conductor alternately positive and negative, creating an oscillating electric field around the conductor. If the frequency of the oscillations is high enough, in the radio frequency range above about 20 kHz, the oscillating coupled electric and magnetic fields will radiate away from the antenna into space as an electromagnetic wave,

1904-432: The development of many aspects of modern society, such as telecommunications , entertainment, education, health care, industry, and security. The main driving force behind the advancement of electronics is the semiconductor industry , which in response to global demand continually produces ever-more sophisticated electronic devices and circuits. The semiconductor industry is one of the largest and most profitable sectors in

1960-874: The early 1960s, and then medium-scale integration (MSI) in the late 1960s, followed by VLSI . In 2008, billion-transistor processors became commercially available. An electronic component is any component in an electronic system either active or passive. Components are connected together, usually by being soldered to a printed circuit board (PCB), to create an electronic circuit with a particular function. Components may be packaged singly, or in more complex groups as integrated circuits . Passive electronic components are capacitors , inductors , resistors , whilst active components are such as semiconductor devices; transistors and thyristors , which control current flow at electron level. Electronic circuit functions can be divided into two function groups: analog and digital. A particular device may consist of circuitry that has either or

2016-452: The electronic logic gates to generate binary states. Highly integrated devices: Electronic systems design deals with the multi-disciplinary design issues of complex electronic devices and systems, such as mobile phones and computers . The subject covers a broad spectrum, from the design and development of an electronic system ( new product development ) to assuring its proper function, service life and disposal . Electronic systems design

2072-435: The field of electronics and the electron age. Practical applications started with the invention of the diode by Ambrose Fleming and the triode by Lee De Forest in the early 1900s, which made the detection of small electrical voltages, such as radio signals from a radio antenna , practicable. Vacuum tubes (thermionic valves) were the first active electronic components which controlled current flow by influencing

2128-456: The flow of individual electrons , and enabled the construction of equipment that used current amplification and rectification to give us radio , television , radar , long-distance telephony and much more. The early growth of electronics was rapid, and by the 1920s, commercial radio broadcasting and telecommunications were becoming widespread and electronic amplifiers were being used in such diverse applications as long-distance telephony and

2184-562: The following ways: The electronics industry consists of various sectors. The central driving force behind the entire electronics industry is the semiconductor industry sector, which has annual sales of over $ 481 billion as of 2018. The largest industry sector is e-commerce , which generated over $ 29 trillion in 2017. The most widely manufactured electronic device is the metal-oxide-semiconductor field-effect transistor (MOSFET), with an estimated 13   sextillion MOSFETs having been manufactured between 1960 and 2018. In

2240-489: The functions of analog circuits were taken over by digital circuits, and modern circuits that are entirely analog are less common; their functions being replaced by hybrid approach which, for instance, uses analog circuits at the front end of a device receiving an analog signal, and then use digital processing using microprocessor techniques thereafter. Sometimes it may be difficult to classify some circuits that have elements of both linear and non-linear operation. An example

2296-462: The global economy, with annual revenues exceeding $ 481 billion in 2018. The electronics industry also encompasses other sectors that rely on electronic devices and systems, such as e-commerce, which generated over $ 29 trillion in online sales in 2017. The identification of the electron in 1897 by Sir Joseph John Thomson , along with the subsequent invention of the vacuum tube which could amplify and rectify small electrical signals , inaugurated

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2352-399: The most widely used electronic device in the world. The MOSFET is the basic element in most modern electronic equipment. As the complexity of circuits grew, problems arose. One problem was the size of the circuit. A complex circuit like a computer was dependent on speed. If the components were large, the wires interconnecting them must be long. The electric signals took time to go through

2408-677: The music recording industry. The next big technological step took several decades to appear, when the first working point-contact transistor was invented by John Bardeen and Walter Houser Brattain at Bell Labs in 1947. However, vacuum tubes played a leading role in the field of microwave and high power transmission as well as television receivers until the middle of the 1980s. Since then, solid-state devices have all but completely taken over. Vacuum tubes are still used in some specialist applications such as high power RF amplifiers , cathode-ray tubes , specialist audio equipment, guitar amplifiers and some microwave devices . In April 1955,

2464-421: The output frequency. Older designs used an oscillator at a lower frequency, which was multiplied by frequency multipliers to get a signal at the desired frequency. Modern designs more commonly use an oscillator at the operating frequency which is stabilized by phase locking to a very stable lower frequency reference, usually a crystal oscillator. Two radio transmitters in the same area that attempt to transmit on

2520-540: The principles of physics to design, create, and operate devices that manipulate electrons and other electrically charged particles . It is a subfield of physics and electrical engineering which uses active devices such as transistors , diodes , and integrated circuits to control and amplify the flow of electric current and to convert it from one form to another, such as from alternating current (AC) to direct current (DC) or from analog signals to digital signals. Electronic devices have hugely influenced

2576-400: The radio waves. When they strike the antenna of a radio receiver , the waves excite similar (but less powerful) radio frequency currents in it. The radio receiver extracts the information from the received waves. A practical radio transmitter mainly consists of the following parts: In higher frequency transmitters, in the UHF and microwave range, free running oscillators are unstable at

2632-434: The range of coverage required by the jurisdiction or authority implementing the system: conventional wireless links in numerous frequency bands, fibre-optic links, or microwave links. In all of these cases the signals are typically backhauled to a central switch of some type where the radio message is processed and resent (repeated) to all transmitter sites where it is required to be heard. In contemporary two-way radio systems

2688-486: The receiver, these pulses were sometimes directly recorded on paper tapes, but more common was audible reception. The pulses were audible as beeps in the receiver's earphones, which were translated back to text by an operator who knew Morse code. These spark-gap transmitters were used during the first three decades of radio (1887–1917), called the wireless telegraphy or "spark" era. Because they generated damped waves , spark transmitters were electrically "noisy". Their energy

2744-540: The reverse definition ("0" is "High") or are current based. Quite often the logic designer may reverse these definitions from one circuit to the next as they see fit to facilitate their design. The definition of the levels as "0" or "1" is arbitrary. Ternary (with three states) logic has been studied, and some prototype computers made, but have not gained any significant practical acceptance. Universally, Computers and Digital signal processors are constructed with digital circuits using Transistors such as MOSFETs in

2800-537: The same corporation that owned or operated the network often manufactured and marketed the listener's radio. Major technical challenges to be overcome when distributing programs over long distances are maintaining signal quality and managing the number of switching/relay points in the signal chain . Early on, programs were sent to remote stations (either owned or affiliated) by various methods, including leased telephone lines, pre-recorded gramophone records and audio tape. The world's first all-radio, non-wireline network

2856-475: The same frequency will interfere with each other, causing garbled reception, so neither transmission may be received clearly. Interference with radio transmissions can not only have a large economic cost, it can be life-threatening (for example, in the case of interference with emergency communications or air traffic control ). For this reason, in most countries, use of transmitters is strictly controlled by law. Transmitters must be licensed by governments, under

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2912-512: The transmitter usually must hold a government license, such as a general radiotelephone operator license , which is obtained by passing a test demonstrating adequate technical and legal knowledge of safe radio operation. Exceptions to the above regulations allow the unlicensed use of low-power short-range transmitters in consumer products such as cell phones , cordless telephones , wireless microphones , walkie-talkies , Wi-Fi and Bluetooth devices, garage door openers , and baby monitors . In

2968-762: The years. For instance, early electronics often used point to point wiring with components attached to wooden breadboards to construct circuits. Cordwood construction and wire wrap were other methods used. Most modern day electronics now use printed circuit boards made of materials such as FR4 , or the cheaper (and less hard-wearing) Synthetic Resin Bonded Paper ( SRBP , also known as Paxoline/Paxolin (trade marks) and FR2) – characterised by its brown colour. Health and environmental concerns associated with electronics assembly have gained increased attention in recent years, especially for products destined to go to European markets. Electrical components are generally mounted in

3024-582: Was claimed to be the Rural Radio Network , a group of six upstate New York FM stations that began operation in June 1948. Terrestrial microwave relay, a technology later introduced to link stations, has been largely supplanted by coaxial cable , fiber , and satellite , which usually offer superior cost-benefit ratios. Many early radio networks evolved into Television networks . Transmitter In electronics and telecommunications ,

3080-440: Was invented by Edwin Armstrong in 1933, who showed that it was less vulnerable to noise and static than AM. The first FM radio station was licensed in 1937. Experimental television transmission had been conducted by radio stations since the late 1920s, but practical television broadcasting didn't begin until the late 1930s. The development of radar during World War II motivated the evolution of high frequency transmitters in

3136-498: Was spread over a broad band of frequencies , creating radio noise which interfered with other transmitters. Damped wave emissions were banned by international law in 1934. Two short-lived competing transmitter technologies came into use after the turn of the century, which were the first continuous wave transmitters: the arc converter ( Poulsen arc ) in 1904 and the Alexanderson alternator around 1910, which were used into

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