ADPCM Noise Shaping Feedback Control for Instability Prevention

The patent implements noise feedback for shaping coding noise by filtering the noise signal and adding it back to the input signal. The feedback loop includes a noise filtering module that processes the quantization noise and a加法 module that combines the filtered noise with the original signal, thereby improving coding quality through spectral shaping while maintaining system stability through controlled feedback gain.

The patent dynamically adjusts the feedback gain parameter based on signal characteristics. By monitoring spectral dynamic range indicators (such as reflection coefficients or signal-to-noise ratio), the system adapts the noise feedback strength to prevent instability with fast-trans transitioning signals while maintaining effectiveness for stable signals, thus resolving the contradiction between coding quality and feedback stability.

The patent employs dynamic control of the noise feedback gain rather than a fixed gain value. The system continuously monitors signal characteristics and adjusts the feedback gain in real-time, increasing gain when signals are stable to improve noise shaping effectiveness, and reducing gain when fast transitions are detected to prevent saturation and acoustic shocks.

The patent detects potential instability conditions (fast transitions, large spectral dynamic range) before they cause saturation or acoustic shocks. By identifying these conditions through spectral analysis and preemptively reducing the noise feedback gain, the system prevents harmful effects before they occur, rather than reacting after saturation has happened.