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FM Band
The FM broadcast band is a range of radio frequencies used for FM broadcasting by radio stations. The range of frequencies used differs between different parts of the world. In Europe and Africa (defined as International Telecommunication Union (ITU) region 1) and in Australia and New Zealand, it spans from 87.5 to 108 megahertz (MHz) - also known as VHF Band II - while in the Americas (ITU region 2) it ranges from 88 to 108 MHz. The FM broadcast band in Japan uses 76 to 95 MHz, and in Brazil, 76 to 108 MHz. The International Radio and Television Organisation (OIRT) band in Eastern Europe is from 65.9 to 74.0 MHz, although these countries now primarily use the 87.5 to 108 MHz band, as in the case of Russia. Some other countries have already discontinued the OIRT band and have changed to the 87.5 to 108 MHz band. Frequency modulation radio originated in the United States during the 1930s; the system was developed by the American electrical engineer Edw ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
North America
North America is a continent in the Northern Hemisphere and almost entirely within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and the Caribbean Sea, and to the west and south by the Pacific Ocean. Because it is on the North American Plate, North American Tectonic Plate, Greenland is included as a part of North America geographically. North America covers an area of about , about 16.5% of Earth's land area and about 4.8% of its total surface. North America is the third-largest continent by area, following Asia and Africa, and the list of continents and continental subregions by population, fourth by population after Asia, Africa, and Europe. In 2013, its population was estimated at nearly 579 million people in List of sovereign states and dependent territories in North America, 23 independent states, or about 7.5% of the world's population. In Americas (terminology)#Human ge ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Canada
Canada is a country in North America. Its ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, covering over , making it the world's second-largest country by total area. Its southern and western border with the United States, stretching , is the world's longest binational land border. Canada's capital is Ottawa, and its three largest metropolitan areas are Toronto, Montreal, and Vancouver. Indigenous peoples have continuously inhabited what is now Canada for thousands of years. Beginning in the 16th century, British and French expeditions explored and later settled along the Atlantic coast. As a consequence of various armed conflicts, France ceded nearly all of its colonies in North America in 1763. In 1867, with the union of three British North American colonies through Confederation, Canada was formed as a federal dominion of four provinces. This began an accretion of provinces an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Edwin Armstrong
Edwin Howard Armstrong (December 18, 1890 – February 1, 1954) was an American electrical engineer and inventor, who developed FM (frequency modulation) radio and the superheterodyne receiver system. He held 42 patents and received numerous awards, including the first Medal of Honor awarded by the Institute of Radio Engineers (now IEEE), the French Legion of Honor, the 1941 Franklin Medal and the 1942 Edison Medal. He was inducted into the National Inventors Hall of Fame and included in the International Telecommunication Union's roster of great inventors. Armstrong attended Columbia University, and served as a professor there for most of his life. Early life Armstrong was born in the Chelsea district of New York City, the oldest of John and Emily (née Smith) Armstrong's three children. His father began working at a young age at the American branch of the Oxford University Press, which published bibles and standard classical works, eventually advancing to the position of v ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Selectivity (radio)
Selectivity is a measure of the performance of a radio receiver to respond only to the radio signal it is tuned to (such as a radio station) and reject other signals nearby in frequency, such as another broadcast on an adjacent channel. Selectivity is usually measured as a ratio in decibels (dB), comparing the signal strength received against that of a similar signal on another frequency. If the signal is at the adjacent channel of the selected signal, this measurement is also known as adjacent-channel rejection ratio (ACRR). Selectivity also provides some immunity to blanketing interference. LC circuits are often used as filters; the Q ("Quality" factor) determines the bandwidth of each LC tuned circuit in the radio. The L/C ratio, in turn, determines their Q and so their selectivity, because the rest of the circuit - the aerial or amplifier feeding the tuned circuit for example - will contain present resistance. For a series resonant circuit, the higher the inductance and the l ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radio Receiver
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 (electromagnetic waves of radio frequency) 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. Radio receivers are essential components of all systems that use radio. The information produced by the receiver may be in the form of sound, video (television), or digital data. A radio receiver may be a separate piece of electronic equipment, or an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Capture Effect
In a radio receiver, the capture effect, or FM capture effect, is a phenomenon associated with FM reception in which only the stronger of two signals at, or near, the same frequency or channel will be demodulated. FM phenomenon The capture effect is defined as the complete suppression of the weaker signal at the receiver's limiter (if present) where the weaker signal is not amplified, but attenuated. When both signals are nearly equal in strength or are fading independently, the receiver may rapidly switch from one to another and exhibit flutter. The capture effect can occur at the signal limiter, or in the demodulation stage for circuits that do not require a signal limiter. Some types of radio receiver circuits have a stronger capture effect than others. The measurement of how well a receiver rejects a second signal on the same frequency is called its capture ratio. It is measured as the lowest ratio of the power of two signals that will result in the suppression of th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Co-channel Interference
Co-channel interference or CCI is crosstalk from two different radio transmitters using the same channel. Co-channel interference can be caused by many factors from weather conditions to administrative and design issues. Co-channel interference may be controlled by various radio resource management schemes. Cellular mobile networks In cellular mobile communication (GSM & LTE Systems, for instance), frequency spectrum is a precious resource which is divided into non-overlapping spectrum bands which are assigned to different cells (In cellular communications, a cell refers to the hexagonal/circular area around the base station antenna). However, after certain geographical distance, these frequency bands are re-used, i.e. the same spectrum bands are reassigned to other distant cells. The co-channel interference arises in the cellular mobile networks owing to this phenomenon of frequency reuse. Thus, besides the intended signal from within the cell, signals at the same frequenc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Italy
Italy ( it, Italia ), officially the Italian Republic, ) or the Republic of Italy, is a country in Southern Europe. It is located in the middle of the Mediterranean Sea, and its territory largely coincides with the homonymous geographical region. Italy is also considered part of Western Europe, and shares land borders with France, Switzerland, Austria, Slovenia and the enclaved microstates of Vatican City and San Marino. It has a territorial exclave in Switzerland, Campione. Italy covers an area of , with a population of over 60 million. It is the third-most populous member state of the European Union, the sixth-most populous country in Europe, and the tenth-largest country in the continent by land area. Italy's capital and largest city is Rome. Italy was the native place of many civilizations such as the Italic peoples and the Etruscans, while due to its central geographic location in Southern Europe and the Mediterranean, the country has also historically been home ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Europe
Europe is a large peninsula conventionally considered a continent in its own right because of its great physical size and the weight of its history and traditions. Europe is also considered a Continent#Subcontinents, subcontinent of Eurasia and it is located entirely in the Northern Hemisphere and mostly in the Eastern Hemisphere. Comprising the westernmost peninsulas of Eurasia, it shares the continental landmass of Afro-Eurasia with both Africa and Asia. It is bordered by the Arctic Ocean to the north, the Atlantic Ocean to the west, the Mediterranean Sea to the south and Asia to the east. Europe is commonly considered to be Boundaries between the continents of Earth#Asia and Europe, separated from Asia by the drainage divide, watershed of the Ural Mountains, the Ural (river), Ural River, the Caspian Sea, the Greater Caucasus, the Black Sea and the waterways of the Turkish Straits. "Europe" (pp. 68–69); "Asia" (pp. 90–91): "A commonly accepted division between Asia and E ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Switzerland
). Swiss law does not designate a ''capital'' as such, but the federal parliament and government are installed in Bern, while other federal institutions, such as the federal courts, are in other cities (Bellinzona, Lausanne, Luzern, Neuchâtel, St. Gallen a.o.). , coordinates = , largest_city = Zürich , official_languages = , englishmotto = "One for all, all for one" , religion_year = 2020 , religion_ref = , religion = , demonym = , german: Schweizer/Schweizerin, french: Suisse/Suissesse, it, svizzero/svizzera or , rm, Svizzer/Svizra , government_type = Federalism, Federal assembly-independent Directorial system, directorial republic with elements of a direct democracy , leader_title1 = Federal Council (Switzerland), Federal Council , leader_name1 = , leader_title2 = , leader_name2 = Walter Thurnherr , legislature = Fe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geneva
Geneva ( ; french: Genève ) frp, Genèva ; german: link=no, Genf ; it, Ginevra ; rm, Genevra is the List of cities in Switzerland, second-most populous city in Switzerland (after Zürich) and the most populous city of Romandy, the French-speaking part of Switzerland. Situated in the south west of the country, where the Rhône exits Lake Geneva, it is the capital of the Canton of Geneva, Republic and Canton of Geneva. The city of Geneva () had a population 201,818 in 2019 (Jan. estimate) within its small municipal territory of , but the Canton of Geneva (the city and its closest Swiss suburbs and exurbs) had a population of 499,480 (Jan. 2019 estimate) over , and together with the suburbs and exurbs located in the canton of Vaud and in the French Departments of France, departments of Ain and Haute-Savoie the cross-border Geneva metropolitan area as officially defined by Eurostat, which extends over ,As of 2020, the Eurostat-defined Functional Urban Area of Geneva was made up of 9 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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