Morse Code Generator

A Rust-based command-line tool for generating Morse code audio and text with configurable speed, tone, and background noise simulation. Useful for amateur radio operators and Morse code learners.

Features

• Multiple Input Modes: Read from stdin, files, or interactive typing
• Configurable Speed: 1-100 WPM (PARIS standard)
• Tone Control: 100-3000 Hz frequency with multiple waveform options
• Realistic QRM: Background noise simulation with 10 levels of interference
• Output Options: Play audio through speakers or save to WAV files
• Practice Modes: Random words, callsigns, Q-codes, and numbers
• Farnsworth Timing: Learn at high character speeds with extended spacing
• Interactive Mode: Real-time typing practice with immediate feedback

Installation

Prerequisites

• Rust and Cargo (1.70.0 or later)
• System audio output (for audio playback)

Building from Source

# Clone the repository
git clone https://github.com/ar/cwgen.git
cd cwgen

# Build in release mode
cargo build --release

# The binary will be at ./target/release/cwgen

Installing via Cargo

cargo install --path .

Usage

Basic Examples

# Play Morse code from stdin
echo "HELLO WORLD" | cwgen

# Play from a file
cwgen --file message.txt

# Text output instead of audio
echo "SOS" | cwgen --output text

# Save to WAV file
echo "CQ CQ DE W1AW" | cwgen --output-file transmission.wav

Configuration Options

# Speed and tone control
cwgen --wpm 15 --tone 800

# Add background noise (QRM levels 0-9)
cwgen --qrm 3

# Different tone shapes
cwgen --tone-shape square
cwgen --tone-shape sawtooth

# Farnsworth timing for learning
cwgen --farnsworth 25 --wpm 15

Interactive Mode

# Type characters and hear Morse code immediately
cwgen --interactive

# Interactive mode with text output
cwgen --interactive --output text

Practice Modes

# Practice with random words
cwgen --practice random-words

# Practice amateur radio callsigns
cwgen --practice callsigns

# Practice Q-codes
cwgen --practice qcodes

# Practice numbers
cwgen --practice numbers

# Custom practice text
cwgen --practice custom --custom-text "CQ TEST DE"

Command Line Reference

USAGE:
    cwgen [OPTIONS]

OPTIONS:
    -f, --file <FILE>              Read text from file instead of stdin
    -h, --help                     Print help information
    -i, --interactive              Interactive typing mode (press Esc to quit)
    -p, --practice <PRACTICE>      Practice mode (random-words, callsigns, qcodes, numbers, custom)
        --custom-text <CUSTOM_TEXT> Custom text for practice mode
    -s, --wpm <WPM>                Speed in WPM (PARIS standard) [default: 20]
    -t, --tone <TONE>              Tone frequency in Hz [default: 700]
    -g, --gap-ms <GAP_MS>          Extra gap between characters in ms [default: 0]
        --output <OUTPUT>          Output mode [default: audio] [possible values: audio, text]
        --qrm <S>                  Background QRM: S0 (no noise) … S9 (extreme) [default: 0]
        --tone-shape <TONE_SHAPE>  Tone shape [default: sine] [possible values: sine, square, sawtooth]
        --farnsworth <FARNSWORTH>  Use Farnsworth timing for learning (specify character speed)
        --output-file <OUTPUT_FILE> Save audio to WAV file instead of playing
        --drift <DRIFT>            Frequency drift percentage (0-100) - simulates homebrew transmitter
    -V, --version                  Print version information

QRM Levels

The --qrm parameter simulates realistic radio interference:

• 0-2: Light noise - Easy copy conditions
• 3-4: Moderate noise - Good for intermediate practice
• 5-6: Significant interference - Requires concentration
• 7-8: Difficult conditions - Expert level
• 9: Extreme interference - Near impossible copy

Practice Tips

For Beginners (5-10 WPM)

cwgen --practice random-words --wpm 10 --qrm 0

Intermediate (10-20 WPM)

cwgen --practice callsigns --wpm 15 --qrm 2

Advanced (20+ WPM)

cwgen --practice qcodes --wpm 25 --qrm 4

Farnsworth Method

Use Farnsworth timing to learn high-speed recognition:

cwgen --practice random-words --farnsworth 25 --wpm 15

Testing

Run the test suite to verify functionality:

# Run all tests
cargo test

# Run specific test modules
cargo test morse
cargo test audio

# Run with detailed output
cargo test -- --nocapture

File Output

Save Morse code transmissions to WAV files for later practice:

# Save a message
echo "THE QUICK BROWN FOX" | cwgen --output-file practice.wav

# Save with specific parameters
echo "CQ CQ DE W1AW" | cwgen --wpm 20 --tone 700 --qrm 3 --output-file qso.wav

Generated WAV files use 8000 Hz sample rate for compact file sizes while maintaining clear Morse code reproduction.

Morse Code Reference

The tool supports standard Morse code characters plus common prosigns:

• Letters: A-Z
• Numbers: 0-9
• Punctuation: . , ? / & ( ) + = @ : ' " !
• Prosigns: <AA> (new line), <AR> (end), <AS> (wait), <BT> (break), <KN> (invite), <SK> (end work)

License

MIT License - see LICENSE file for details.

Contributing

Contributions are welcome! Please feel free to submit pull requests or open issues for bugs and feature requests.

Troubleshooting

No Audio Output

• Check system audio settings
• Verify audio permissions
• Try using --output-file to test audio generation

Build Issues

• Ensure Rust is up to date: rustup update
• Clear cargo cache: cargo clean

Performance

• For long texts, use file output instead of real-time playback
• Lower sample rate (already optimized to 8000 Hz) keeps files small

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Happy copying! 73 de CX4CC.