Sine Wave Array Generator

A command-line tool to generate sine wave audio buffers.

Features

• Multiple Sample Rates: 16kHz, 44.1kHz, 48kHz (and custom)
• Bit Depths: 16-bit, 24-bit, 32-bit audio
• Channel Configurations: Mono (1 channel) or Stereo (2 channels)
• Custom Duration: Generate any length of audio in milliseconds
• Multiple Output Formats: Hex, C arrays, Rust arrays, raw binary, Waveform Audio File Format (PCM)
• Analysis Mode: Calculate buffer requirements and efficiency

Use Cases

• Embedded Development: Generate test data for audio devices
• Hardware Testing: Create reference signals for audio quality testing
• Education: Understand digital audio generation and USB audio packetization
• Prototyping: Quickly generate audio buffers without external tools

Prerequisites

• Rust toolchain (1.70+)

Build from Source

# Clone and build
git clone <repository-url>
cd singen
cargo build --release

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

Basic Examples

# Default settings (440Hz, 16kHz, stereo 16-bit, 1ms)
./singen

# Generate 1kHz sine at 48kHz for 10ms, 24-bit
./singen -f 1000 -r 48000 -b 24 -d 10

# Mono output with C array format
./singen -c 1 -o carray

# Optimize for USB packets (64-byte boundaries)
./singen -r 32000 -d 1 -p

# Rust array for embedded use
./singen -r 16000 -d 1 -o rustarray

# Just show info without generating data
./singen -a

# Raw binary output (pipe to file)
./singen -r 16000 -d 10 -o raw > sinewave.bin

# Wav output (pipe to file)
./singen -d 1000 -f 1000 -o wav > sinewave.wav

Command Line Options

Sine Wave Generator for USB Audio Testing
Usage: singen [OPTIONS]

Options:
  -f, --frequency FREQ     Sine wave frequency in Hz (default: 440.0)
  -r, --rate RATE          Sample rate in Hz (default: 16000)
                           Supported: 16000, 44100, 48000
  -c, --channels CH        Number of channels (1=mono, 2=stereo, default: 2)
  -b, --bits BITS          Bit depth: 16, 24, or 32 (default: 16)
  -d, --duration MS        Duration in milliseconds (default: 1.0)
  -o, --output FORMAT      Output format:
                           hex      - Hexadecimal values (default)
                           carray   - C-style array declaration
                           rustarray - Rust array declaration
                           raw      - Raw binary bytes (stdout)
                           info     - Only show buffer info, no data
  -p, --packet-mode        Optimize for USB packets (64-byte boundaries)
  -a, --analyze            Analyze only (don't generate data)
  -h, --help               Show this help message

Examples:
  singen -f 1000 -r 48000 -b 16 -d 10 -o carray
  singen --frequency 440 --rate 44100 --channels 1 --bits 24
  singen -r 16000 -d 1 -o rustarray -p

Output Formats

1. Hex Format (Default)

Prints hexadecimal values of the generated buffer:

[0x00, 0x00, 0x00, 0x00, 0x01, 0x16, 0x01, 0x16, 0x5B, 0x2B, 0x5B, 0x2B, 0x6A, 0x3F, 0x6A, 0x3F,
 0x96, 0x51, 0x96, 0x51, 0x54, 0x61, 0x54, 0x61, 0x2B, 0x6E, 0x2B, 0x6E, 0xBB, 0x77, 0xBB, 0x77,
 ...]

2. C Array Format

Generates C/C++ compatible array declarations:

// Sine wave: 440 Hz, 1 ms, 16-bit, 2 channels
// Sample rate: 16000 Hz
// Total bytes: 64
const uint8_t SINE_16000HZ_1MS_16BIT_2CH[64] = {
    0x00, 0x00, 0x00, 0x00, 0x01, 0x16, 0x01, 0x16, 0x5B, 0x2B, 0x5B, 0x2B, 0x6A, 0x3F, 0x6A, 0x3F,
    0x96, 0x51, 0x96, 0x51, 0x54, 0x61, 0x54, 0x61, 0x2B, 0x6E, 0x2B, 0x6E, 0xBB, 0x77, 0xBB, 0x77,
    ...
};

3. Rust Array Format

Generates Rust array declarations:

// Sine wave: 440 Hz, 1 ms, 16-bit, 2 channels
// Sample rate: 16000 Hz
// Total bytes: 64
pub const SINE_16000HZ_1MS_16BIT_2CH: [u8; 64] = [
    0x00, 0x00, 0x00, 0x00, 0x01, 0x16, 0x01, 0x16, 0x5B, 0x2B, 0x5B, 0x2B, 0x6A, 0x3F, 0x6A, 0x3F,
    0x96, 0x51, 0x96, 0x51, 0x54, 0x61, 0x54, 0x61, 0x2B, 0x6E, 0x2B, 0x6E, 0xBB, 0x77, 0xBB, 0x77,
    ...
];

4. Raw Binary Format

Outputs raw binary data to stdout (useful for piping to files or other programs).

5. Info Format

Shows detailed analysis without generating the actual data buffer.

Example Analysis Output

Sine Wave Generator - Configuration
=====================================
Frequency:      440.0 Hz
Sample Rate:    16000 Hz
Channels:       2 (stereo)
Bit Depth:      16-bit
Duration:       1.0 ms

Buffer Analysis:
  Samples:      16
  Total bytes:  64

Frequency Analysis:
  Period:       36.36 samples
  Full cycles:  0.44

Audio Generation Algorithm

The tool uses high-precision floating-point math to generate sine waves:

• Phase accumulation with modulo wrapping to prevent discontinuities
• Proper handling of 24-bit signed audio (sign extension)
• Accurate duration calculation with rounding for non-integer sample rates

Dependencies

• Standard library only (no external dependencies)

For C/C++ Projects

1. Generate a C array:

   ./singen -r 16000 -d 1 -o carray > sine_buffer.h

2. Include in your project:

   #include "sine_buffer.h"
   
   // Use SINE_16000HZ_1MS_16BIT_2CH array

For Rust Embedded Projects

1. Generate a Rust array:

   ./singen -r 16000 -d 1 -o rustarray > src/sine_buffer.rs

2. Include in your project:

   mod sine_buffer;
   use sine_buffer::SINE_16000HZ_1MS_16BIT_2CH;

Generate Test Patterns For Testing Audio:

# Generate multiple test frequencies
for freq in 440 1000 2000 4000; do
  ./singen -f $freq -r 48000 -d 100 -o raw > test_${freq}hz.bin
done

Common Issues

Phase discontinuities in generated audio

• The code uses modulo phase wrapping to prevent discontinuities
• If you still hear clicks, try generating longer buffers or using integer frequency multiples of sample rate

License

This project is available for use under the MIT License.