Morse Code Translator, CW Audio Oscillator & Visual Beacon (2026)

International Morse Code timing is based on a single base unit: the duration of one dot (`dit`). A dash (`dah`) lasts exactly 3 units; the intra-character gap between dots and dashes inside the same letter is 1 unit; the inter-character gap between letters is 3 units; and the gap between words is 7 units.

The standard reference word for measuring Morse Code speed is `'PARIS'`, which requires exactly 50 timing units (including its trailing word space). At 1 Word Per Minute (60,000 milliseconds per minute), 50 units take 60,000 ms, so 1 unit takes $60000 / 50 = 1200\text{ ms}$. Therefore, at any speed $W$ WPM, a single dot lasts $T_{\text{dit}} = 1200 / W$ milliseconds (e.g., 60 ms at 20 WPM).

Samuel Morse and Alfred Vail designed the code using variable-length prefix encoding (an early precursor to Huffman coding) after counting physical lead type pieces in a Morristown, New Jersey printing press. The most frequent letters in English (`E` and `T`) received the shortest 1-symbol codes, while rare letters (`Q`, `Z`, `J`, `X`) received 4-symbol combinations.

`SOS` does not stand for 'Save Our Ship' or 'Save Our Souls'—it was adopted by the 1906 Berlin International Radiotelegraphic Convention because three dots, three dashes, and three dots form an unmistakable, symmetric rhythm. Strictly speaking, it is transmitted as a continuous 9-element prosign (`...---...`) without the 3-unit inter-character spaces between S, O, and S.

Instantaneously switching a sine-wave oscillator from 0.0 to 1.0 amplitude creates high-frequency spectral splatter known in radio telegraphy as 'key clicks'. Our WebAudio engine applies a 5-millisecond linear/raised-cosine gain ramp on the rising and falling edge of every dit and dah for smooth, ear-friendly sidetone audio.