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Multi Rolle Radio
Multi Rolle Radio (English: Multi Role Radio) is a modular radio set which supports high speed frequency hopping and strong encryption. It was ordered in early 1993 and first put to operative use in mid-1995. It operates on standard military VHF frequencies ranging from 30.000 to 87.975 MHz. The system was developed in Norway, mainly by Kongsberg Defence Communication and Thales Group Norway, with support from the Norwegian Defence Research Establishment. It has been exported to Hungary. The radio is modular, and can be configured both as portable (PRC) and vehicle-mounted (VRC). The VRC can be fitted with two receive/transmit modules in a single mounting, for use as a relay. Although most transmit specifications are classified, it is known that the radio uses Gaussian Minimum Shift Keying and M-ary encoding. It can also be used in an analog FM mode, in which it is compatible with other radios like AN/PRC-77 and civilian radios. It has several features besides being a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Frequency Hopping
Frequency-hopping spread spectrum (FHSS) is a method of transmitting radio signals by rapidly changing the carrier frequency among many distinct frequencies occupying a large spectral band. The changes are controlled by a code known to both transmitter and receiver. FHSS is used to avoid interference, to prevent eavesdropping, and to enable code-division multiple access (CDMA) communications. The available frequency band is divided into smaller sub-bands. Signals rapidly change ("hop") their carrier frequencies among the center frequencies of these sub-bands in a predetermined order. Interference at a specific frequency will affect the signal only during a short interval. FHSS offers four main advantages over a fixed-frequency transmission: # FHSS signals are highly resistant to narrowband interference because the signal hops to a different frequency band. # Signals are difficult to intercept if the frequency-hopping pattern is not known. # Jamming is also difficult if the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Encryption
In cryptography, encryption is the process of encoding information. This process converts the original representation of the information, known as plaintext, into an alternative form known as ciphertext. Ideally, only authorized parties can decipher a ciphertext back to plaintext and access the original information. Encryption does not itself prevent interference but denies the intelligible content to a would-be interceptor. For technical reasons, an encryption scheme usually uses a pseudo-random encryption key generated by an algorithm. It is possible to decrypt the message without possessing the key but, for a well-designed encryption scheme, considerable computational resources and skills are required. An authorized recipient can easily decrypt the message with the key provided by the originator to recipients but not to unauthorized users. Historically, various forms of encryption have been used to aid in cryptography. Early encryption techniques were often used in milit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Very High Frequency
Very high frequency (VHF) is the ITU designation for the range of radio frequency electromagnetic waves ( radio waves) from 30 to 300 megahertz (MHz), with corresponding wavelengths of ten meters to one meter. Frequencies immediately below VHF are denoted high frequency (HF), and the next higher frequencies are known as ultra high frequency (UHF). VHF radio waves propagate mainly by line-of-sight, so they are blocked by hills and mountains, although due to refraction they can travel somewhat beyond the visual horizon out to about 160 km (100 miles). Common uses for radio waves in the VHF band are Digital Audio Broadcasting (DAB) and FM radio broadcasting, television broadcasting, two-way land mobile radio systems (emergency, business, private use and military), long range data communication up to several tens of kilometers with radio modems, amateur radio, and marine communications. Air traffic control communications and air navigation systems (e.g. VOR and I ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Norway
Norway, officially the Kingdom of Norway, is a Nordic country in Northern Europe, the mainland territory of which comprises the western and northernmost portion of the Scandinavian Peninsula. The remote Arctic island of Jan Mayen and the archipelago of Svalbard also form part of Norway. Bouvet Island, located in the Subantarctic, is a dependency of Norway; it also lays claims to the Antarctic territories of Peter I Island and Queen Maud Land. The capital and largest city in Norway is Oslo. Norway has a total area of and had a population of 5,425,270 in January 2022. The country shares a long eastern border with Sweden at a length of . It is bordered by Finland and Russia to the northeast and the Skagerrak strait to the south, on the other side of which are Denmark and the United Kingdom. Norway has an extensive coastline, facing the North Atlantic Ocean and the Barents Sea. The maritime influence dominates Norway's climate, with mild lowland temperatures on the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kongsberg Defence & Aerospace
Kongsberg Defence & Aerospace is one of three business units of Kongsberg Gruppen (KONGSBERG) of Norway and the supplier of defence and space related systems and products, mainly anti-ship missiles, military communications, and command and weapons control systems for naval vessels and air-defence applications. Today, the company is probably best known abroad for its development/industrialisation and production of the first passive IR homing anti-ship missile of the western world, the Penguin, starting delivery in the early 1970s (when Kongsberg Defence & Aerospace was part of KONGSBERG's predecessor ''Kongsberg Våpenfabrikk''). As of 2021, Kongsberg Defence & Aerospace had 3,500 employees. Space related activities are conducted within Kongsberg Defence & Aerospace's Space & Surveillance division and ''Kongsberg Satellite Services''. Notable space related products from Kongsberg Defence & Aerospace are the Booster Attachment and Release Mechanisms for ESA's Ariane 5. In the early ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thales Group
Thales Group () is a French multinational company that designs, develops and manufactures electrical systems as well as devices and equipment for the aerospace, defence, transportation and security sectors. The company is headquartered in Paris' business district, La Défense, and its stock is listed on the Euronext Paris. Having been known as Thomson-CSF since its foundation in 1968, the company was rebranded ''Thales'' (named after the Greek philosopher Thales and pronounced , reflecting its pronunciation in French) in December 2000. A communication audit, launched in spring that year, highlighted Thomson-CSF's image deficit, particularly among the young French graduates it was seeking to recruit. The wish to liven up its image as well as the expansion of its business worldwide were cited among the reasons for the change. Thales is partially owned by the French State and operates in more than 56 countries. It had 80,000 employees and generated €18.4 billion in revenues ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Norwegian Defence Research Establishment
The Norwegian Defence Research Establishment (''Forsvarets forskningsinstitutt'' – ''FFI'') is a research institute that conducts research and development on behalf of the Norwegian Armed Forces and provides expert advice to political and military defence leaders. In particular, its task is to keep track of advances in the fields of science and military technology which might affect the assumptions on which Norwegian security policy and/or defence planning is based. History The institute was established in 1946. Its roots lie in Norwegian participation in British scientific research during the Second World War (see Allied technological cooperation during World War II). Many Norwegian scientists and technologists took part during the period when Germany occupied Norway between 1940 and 1945. FFI has 714 employees, of which approximately 360 are scientists and engineers. The main location of the institute is at Kjeller near Lillestrøm, 20 km east of the country's cap ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Relay
A relay Electromechanical relay schematic showing a control coil, four pairs of normally open and one pair of normally closed contacts An automotive-style miniature relay with the dust cover taken off A relay is an electrically operated switch. It consists of a set of input terminals for a single or multiple control signals, and a set of operating contact terminals. The switch may have any number of contacts in multiple contact forms, such as make contacts, break contacts, or combinations thereof. Relays are used where it is necessary to control a circuit by an independent low-power signal, or where several circuits must be controlled by one signal. Relays were first used in long-distance telegraph circuits as signal repeaters: they refresh the signal coming in from one circuit by transmitting it on another circuit. Relays were used extensively in telephone exchanges and early computers to perform logical operations. The traditional form of a relay uses an electromagnet to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Minimum-shift Keying
In digital modulation, minimum-shift keying (MSK) is a type of continuous-phase frequency-shift keying that was developed in the late 1950s by Collins Radio employees Melvin L. Doelz and Earl T. Heald. Similar to OQPSK, MSK is encoded with bits alternating between quadrature components, with the Q component delayed by half the symbol period. However, instead of square pulses as OQPSK uses, MSK encodes each bit as a half sinusoid. This results in a constant-modulus signal (constant envelope signal), which reduces problems caused by non-linear distortion. In addition to being viewed as related to OQPSK, MSK can also be viewed as a continuous-phase frequency-shift keyed ( CPFSK) signal with a frequency separation of one-half the bit rate. In MSK the difference between the higher and lower frequency is identical to half the bit rate. Consequently, the waveforms used to represent a 0 and a 1 bit differ by exactly half a carrier period. Thus, the maximum frequency deviation is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
FM Broadcasting
FM broadcasting is a method of radio broadcasting using frequency modulation (FM). Invented in 1933 by American engineer Edwin Armstrong, wide-band FM is used worldwide to provide high fidelity sound over broadcast radio. FM broadcasting is capable of higher fidelity—that is, more accurate reproduction of the original program sound—than other broadcasting technologies, such as AM broadcasting. It is also less susceptible to common forms of interference, reducing static and popping sounds often heard on AM. Therefore, FM is used for most broadcasts of music or general audio (in the audio spectrum). FM radio stations use the very high frequency range of radio frequencies. Broadcast bands Throughout the world, the FM broadcast band falls within the VHF part of the radio spectrum. Usually 87.5 to 108.0 MHz is used, or some portion thereof, with few exceptions: * In the former Soviet republics, and some former Eastern Bloc countries, the older 65.8–74 M ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
AN/PRC-77 Portable Transceiver
AN/PRC 77 Radio Set is a manpack, portable VHF FM combat-net radio transceiver manufactured by Associated Industries Manufacturer's website. and used to provide short-range, two-way voice communication. In the Joint Electronics Type Designation System (JETDS), AN/PRC translates to "Army/Navy, Portable, Radio, Communication." History The AN/PRC-77 entered service in 1968 during the Vietnam War as an upgrade to the earlier AN/PRC-25. It differs from its predecessor mai ...[...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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