scbe-audio-intent

name	scbe-audio-intent
description	Encode and decode intent values as phase-modulated audio waveforms using FFT-based demodulation. Use when working with the audio intent layer, phase encoding/recovery, or the symphonic cipher carrier signal.

SCBE Audio Intent

Use this skill for phase-modulated intent encoding and decoding in the SCBE-AETHERMOORE audio layer.

Core Mechanism

Intent values ∈ [0, 1] are encoded as phase offsets on a carrier frequency, then recovered via FFT peak analysis.

Encoding (Phase Modulation)

wave(t) = cos(2π · f_carrier · t + 2π · intent) + noise

• f_carrier = 440 Hz (A4)
• Sample rate = 44100 Hz
• Duration = 0.5 seconds
• Gaussian noise σ = 0.1 added for transmission simulation

Decoding (FFT Demodulation)

1. Compute FFT of received waveform.
2. Find peak index in positive-frequency half.
3. Extract phase angle at peak: angle(FFT[peak_idx]).
4. Normalize: intent_recovered = (phase mod 2π) / 2π.

Audio Constants

Name	Value	Purpose
CARRIER_FREQ	440.0	Base carrier (Hz)
SAMPLE_RATE	44100	Samples per second
DURATION	0.5	Waveform length (sec)

Workflow

1. Accept intent value ∈ [0, 1].
2. Generate time vector: linspace(0, DURATION, SAMPLE_RATE * DURATION).
3. Produce carrier with phase offset: cos(2π·440·t + 2π·intent).
4. Add Gaussian noise.
5. To recover: FFT → peak detection → phase extraction → normalize.

Accuracy Considerations

• Phase recovery is approximate due to noise and FFT bin resolution.
• For governance decisions, the recovered intent is compared against known target (e.g., 0.75) with tolerance ±0.1.
• Higher sample rates or longer durations improve phase resolution.

Integration Points

• The recovered intent feeds into the coherence check in governance_9d.
• Coherence is HIGH (0.95) when |intent - 0.75| < 0.1, LOW (0.4) otherwise.
• The audio layer provides a physical-channel encoding for the v2 (Intent Phase) component.

Guardrails

1. Intent must be clamped to [0, 1] before encoding.
2. Only use positive-frequency half of FFT for peak detection.
3. Phase normalization must use modulo 2π before dividing.
4. Noise level (σ=0.1) is fixed for reproducibility; do not increase without testing recovery accuracy.