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  2. Beat frequency oscillator - Wikipedia

    en.wikipedia.org/wiki/Beat_frequency_oscillator

    Add-on 455 kHz homemade BFO board. In a radio receiver, a beat frequency oscillator or BFO is a dedicated oscillator used to create an audio frequency signal from Morse code radiotelegraphy ( CW) transmissions to make them audible. The signal from the BFO is mixed with the received signal to create a heterodyne or beat frequency which is heard ...

  3. Telegraph key - Wikipedia

    en.wikipedia.org/wiki/Telegraph_key

    A telegraph key or Morse key is a specialized electrical switch used by a trained operator to transmit text messages in Morse code in a telegraphy system. Keys are used in all forms of electrical telegraph systems, including landline (also called wire) telegraphy and radio (also called wireless) telegraphy. An operator uses the telegraph key to ...

  4. Charlieplexing - Wikipedia

    en.wikipedia.org/wiki/Charlieplexing

    In the following Arduino code example, the circuit uses ATtiny 8-pin microcontroller which has 5 I/O pins to create a 7-segment display. Since a 7-segment display only requires control of 7 individual LEDs, we use 4 of the ATtiny I/O pins as Charlieplexed outputs ( n ( n - 1)), i.e. the 4 pins could be used to control up to 12 individual LEDs ...

  5. QSK operation (full break-in) - Wikipedia

    en.wikipedia.org/wiki/QSK_operation_(full_break-in)

    Full break-in or QSK operation, [1] [2] [3] is a hardware supported Morse code communications channel turn over communications protocol. So, full break-in is also a duplexing protocol, which facilitates a style of two-way Morse code communications on traditional half-duplex radiotelegraph channels that closely simulates full-duplex channel ...

  6. Prosigns for Morse code - Wikipedia

    en.wikipedia.org/wiki/Prosigns_for_Morse_code

    The procedure signs below are compiled from the official specification for Morse Code, ITU-R M.1677, International Morse Code, while others are defined the International Radio Regulations for Mobile Maritime Service, including ITU-R M.1170, ITU-R M.1172, and the Maritime International Code of Signals, with a few details of their usage appearing ...

  7. Morse code - Wikipedia

    en.wikipedia.org/wiki/Morse_code

    Morse code is a method used in telecommunication to encode text characters as standardized sequences of two different signal durations, called dots and dashes, or dits and dahs. [3] [4] Morse code is named after Samuel Morse, one of the early developers of the system adopted for electrical telegraphy . International Morse code encodes the 26 ...

  8. Distribution board - Wikipedia

    en.wikipedia.org/wiki/Distribution_board

    A distribution board (also known as panelboard, breaker panel, electric panel, fuse box or DB box) is a component of an electricity supply system that divides an electrical power feed into subsidiary circuits while providing a protective fuse or circuit breaker for each circuit in a common enclosure. Normally, a main switch, and in recent ...

  9. Heterodyne - Wikipedia

    en.wikipedia.org/wiki/Heterodyne

    Thus the Morse code "dots" and "dashes" are audible as beeping sounds. This technique is still used in radio telegraphy, the local oscillator now being called the beat frequency oscillator or BFO. Fessenden coined the word heterodyne from the Greek roots hetero-"different", and dyn-"power" (cf. δύναμις or dunamis).