morse

Morse Code Practice with Nelson

International Morse code for Nelson:

encode text to dots and dashes and decode it back, look up the code table, turn a message into keyed-tone audio, play it or save it to a WAV file, and practice with an interactive trainer.

Load

run('/path/to/morse/loader.m')

Quick start

morse.encode('SOS')                 % '... --- ...'
morse.decode('... --- ...')         % 'SOS'
morse.decode(morse.encode('HELLO WORLD'))   % 'HELLO WORLD'

morse.encode('<AR>')                % prosign, run together: '.-.-.'
morse.encode(char(201))             % accented letters (E acute): '..-..'
morse.encode({'SOS', 'OK'})         % string array / cellstr join into words

morse.table()                       % print the ITU-R M.1677-1 table
morse.prosigns()                    % common prosigns (AR, SK, BT, ...)
morse.isvalid('... --- ...')        % true

morse.play('CQ CQ', 'WPM', 18, 'Frequency', 600)   % send it to the speaker
morse.towav('sos.wav', 'SOS')                       % or write a WAV file
morse.fromwav('sos.wav')                            % ... and decode it back: 'SOS'

morse.practice()                    % open the interactive trainer

Functions

Function	Purpose
morse.encode(text, ...)	Text to Morse code. Accepts char/string/cellstr; options: LetterSeparator, WordSeparator, Dot, Dash, OnUnknown, Prosigns.
morse.decode(code, ...)	Morse code back to text. Options: Dot, Dash, OnUnknown, Placeholder.
morse.table()	The code table, printed or returned as an N-by-2 cell array.
morse.prosigns()	The common procedural signals (prosigns).
morse.isvalid(code)	True when every group of a Morse string decodes.
morse.tone(input, ...)	Synthesize the audio samples [y, fs] (no playback).
morse.play(input, ...)	Synthesize and play on the default output device (Block, false for non-blocking).
morse.towav(file, input, ...)	Synthesize and write a WAV file.
morse.fromwav(file, ...)	Detect the tone in a WAV file and decode it back to text.
morse.practice()	Interactive trainer window.

Audio options

morse.tone, morse.play and morse.towav share the same options:

• WPM (default 20) — element speed in words per minute (PARIS convention).
• Farnsworth (default []) — when set below WPM, keeps the dots and dashes crisp while stretching the gaps between letters and words (ARRL timing), for learning at a slower overall pace.
• Frequency (default 700) — tone frequency in hertz.
• SampleRate (default 8000) — samples per second.
• Amplitude (default 0.6) — peak amplitude in [0, 1].
• RampMs (default 5) — raised-cosine edge ramp, in milliseconds, to avoid clicks.
• Input ('auto', 'text' or 'code') — how the argument is interpreted; 'auto' tells 'SOS' from '... --- ...' apart.

morse.play, morse.towav and morse.fromwav use Nelson's core audio module. morse.fromwav measures the element speed from the audio (the WPM need not be known), finds the tone frequency automatically for a clean recording (pass Frequency to lock onto a known tone in noise), and separates the letter and word gaps by their own clustering, so Farnsworth-spaced sending decodes too.

Examples

See examples/morse_demo.m for a short tour.

Tests

test_run('/path/to/morse/tests/test_morse.m')

License

LGPL-3.0-or-later.