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Morse code. Morse code is a telecommunications method which encodes 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 .
American Morse code. American Morse Code — also known as Railroad Morse—is the latter-day name for the original version of the Morse Code developed in the mid-1840s, by Samuel Morse and Alfred Vail for their electric telegraph. The "American" qualifier was added because, after most of the rest of the world adopted " International Morse Code ...
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 ...
Acoustic telegraphy (also known as harmonic telegraphy) was a name for various methods of multiplexing (transmitting more than one) telegraph messages simultaneously over a single telegraph wire by using different audio frequencies or channels for each message. A telegrapher used a conventional Morse key to tap out the message in Morse code.
The spark gap is inside the box with the transparent cover at top center. A spark-gap transmitter is an obsolete type of radio transmitter which generates radio waves by means of an electric spark. [ 1][ 2] Spark-gap transmitters were the first type of radio transmitter, and were the main type used during the wireless telegraphy or "spark" era ...
A waterfall display depicting several PSK31 transmissions at around 14,070 kHz. The green lines indicate a station that is transmitting. PSK31 or "Phase Shift Keying, 31 Baud", also BPSK31 and QPSK31, is a popular computer-sound card-generated radioteletype mode, used primarily by amateur radio operators to conduct real-time keyboard-to-keyboard chat, most often using frequencies in the high ...
Pulse-code modulation ( PCM) is a method used to digitally represent analog signals. It is the standard form of digital audio in computers, compact discs, digital telephony and other digital audio applications. In a PCM stream, the amplitude of the analog signal is sampled at uniform intervals, and each sample is quantized to the nearest value ...
Visual mnemonic charts have been devised over the ages. Baden-Powell included one in the Girl Guides handbook [1] in 1918. A contemporary Morse code chart. Here is a more up-to-date version, ca. 1988: Other visual mnemonic systems have been created for Morse code, mapping the elements of the Morse code characters onto pictures for easy ...