48 kHz ACOUSTIC BYTE BEACON

PROTOCOL AND FAULT TOLERANCE

A 21 kHz pilot is followed by complementary frequency pairs spaced 50 Hz apart. Each protected bit activates either its 0-frequency or its 1-frequency. The receiver tracks clock drift using the pilot.

Base/pilot frequency (Hz) Carrier spacing (Hz) Error-correcting code Maximum corrected carrier errors

Pilot relative strength Protected bits 24 Occupied range 21000–23400 Hz Code capability Correct 3 errors

SENDER — CONTINUOUS SEND-ONLY BEACON

Byte value (0–255) Output level: 80% Speaker Download duration (seconds)

Encoded carriers: —

Beacon stopped.

RECEIVER SENSITIVITY

Sensitivity preset Minimum pilot SNR (dB) Minimum carrier SNR (dB) Minimum pair margin (dB)

Maximum weak carrier pairs Pilot tracking range (±Hz) Analysis bandwidth (Hz) FFT size

Spectrum smoothing Vote window Votes required Decode interval (ms)

MICROPHONE DECODER

Microphone Requested sample rate 48000 Hz Actual input sample rate — Tracked frequency offset —

Microphone inactive. HTTPS or localhost is normally required.

DECODED BYTE

—

Waiting for microphone.

Received protected bits: —