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  2. Radio frequency - Wikipedia

    en.wikipedia.org/wiki/Radio_frequency

    Radio frequency. Radio frequency ( RF) is the oscillation rate of an alternating electric current or voltage or of a magnetic, electric or electromagnetic field or mechanical system in the frequency [ 1] range from around 20 kHz to around 300 GHz. This is roughly between the upper limit of audio frequencies and the lower limit of infrared ...

  3. Radio-frequency engineering - Wikipedia

    en.wikipedia.org/wiki/Radio-frequency_engineering

    v. t. e. Radio-frequency (RF) engineering is a subset of electrical engineering involving the application of transmission line, waveguide, antenna, radar, and electromagnetic field principles to the design and application of devices that produce or use signals within the radio band, the frequency range of about 20 kHz up to 300 GHz. [ 1][ 2][ 3]

  4. Radio-frequency identification - Wikipedia

    en.wikipedia.org/wiki/Radio-frequency_identification

    Radio-frequency identification ( RFID) uses electromagnetic fields to automatically identify and track tags attached to objects. An RFID system consists of a tiny radio transponder called a tag, a radio receiver, and a transmitter. When triggered by an electromagnetic interrogation pulse from a nearby RFID reader device, the tag transmits ...

  5. Rural Free Delivery - Wikipedia

    en.wikipedia.org/wiki/Rural_Free_Delivery

    Rural Free Delivery ( RFD ), since 1906 officially rural delivery, is a program of the United States Post Office Department to deliver mail directly to rural destinations. The program began in the late 19th century. Before that, people living in rural areas had to pick up mail themselves at sometimes distant post offices or pay private carriers ...

  6. Radio spectrum - Wikipedia

    en.wikipedia.org/wiki/Radio_spectrum

    The radio spectrum is the part of the electromagnetic spectrum with frequencies from 3 Hz to 3,000 GHz (3 THz ). Electromagnetic waves in this frequency range, called radio waves, are widely used in modern technology, particularly in telecommunication. To prevent interference between different users, the generation and transmission of radio ...

  7. RF (disambiguation) - Wikipedia

    en.wikipedia.org/wiki/RF_(disambiguation)

    Representative fraction. Rest frame. Retardation factor in a chromatographic system. Radiative forcing, the change in energy flux in the atmosphere caused by climate change factors. Random forest, an ensemble learning method in data science. Rutherfordium, symbol Rf, a chemical element. Canon RF mount, interchangeable camera lens mount.

  8. RF and microwave filter - Wikipedia

    en.wikipedia.org/wiki/RF_and_microwave_filter

    Radio frequency (RF) and microwave filters represent a class of electronic filter, designed to operate on signals in the megahertz to gigahertz frequency ranges ( medium frequency to extremely high frequency ). It is component that is used in electronic systems to pass or reject specific frequencies and attenuate of unwanted signals within the ...

  9. RF connector - Wikipedia

    en.wikipedia.org/wiki/RF_connector

    An RF connector ( radio frequency connector) is an electrical connector designed to work at radio frequencies in the multi-megahertz range. RF connectors are typically used with coaxial cables and are designed to maintain the shielding that the coaxial design offers. Better models also minimize the change in transmission line impedance at the ...