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  2. Two-way radio - Wikipedia

    en.wikipedia.org/wiki/Two-way_radio

    Naval air traffic controller communicates with aircraft over a two-way radio headset A variety of portable handheld two-way radios for private use. A two-way radio is a radio transceiver (a radio that can both transmit and receive radio waves), which is used for bidirectional person-to-person voice communication with other users with similar radios, [1] in contrast to a broadcast receiver ...

  3. Frequency modulation - Wikipedia

    en.wikipedia.org/wiki/Frequency_modulation

    [2] Frequency modulation is widely used for FM radio broadcasting. It is also used in telemetry, radar, seismic prospecting, and monitoring newborns for seizures via EEG, [3] two-way radio systems, sound synthesis, magnetic tape-recording systems and some video-transmission systems.

  4. Frequency allocation - Wikipedia

    en.wikipedia.org/wiki/Frequency_allocation

    The International Telecommunication Union defines frequency allocation as being of "a given frequency band for the purpose of its use by one or more terrestrial or space radiocommunication services or the radio astronomy service under specified conditions". [2] Frequency allocation is also a special term, used in national frequency ...

  5. Trunked radio system - Wikipedia

    en.wikipedia.org/wiki/Trunked_radio_system

    A trunked radio system is a two-way radio system that uses a control channel to automatically assign frequency channels to groups of user radios. In a traditional half-duplex land mobile radio system a group of users (a talkgroup) with mobile and portable two-way radios communicate over a single shared radio channel, with one user at a time ...

  6. Radio spectrum - Wikipedia

    en.wikipedia.org/wiki/Radio_spectrum

    A radio band is a small frequency band (a contiguous section of the range of the radio spectrum) in which channels are usually used or set aside for the same purpose. To prevent interference and allow for efficient use of the radio spectrum, similar services are allocated in bands.

  7. Continuous Tone-Coded Squelch System - Wikipedia

    en.wikipedia.org/wiki/Continuous_Tone-Coded...

    The use of digital squelch on a channel that has existing tone squelch users precludes the use of the 131.8 and 136.5 Hz tones as the digital bit rate is 134.4 bits per second and the decoders set to those two tones will sense an intermittent signal (referred to in the two-way radio field as "falsing" the decoder). [2]

  8. Radio-frequency engineering - Wikipedia

    en.wikipedia.org/wiki/Radio-frequency_engineering

    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]

  9. Narrowband - Wikipedia

    en.wikipedia.org/wiki/Narrowband

    In radio communications, a narrowband channel is a channel in which the bandwidth of the message does not significantly exceed the channel's coherence bandwidth. In the study of wired channels, narrowband implies that the channel under consideration is sufficiently narrow that its frequency response can be considered flat.