Feedback control applied to speech coding

Adaptive speech coders typically include an adaptive predictor and an adaptive quantizer. A prediction error signal is created by subtracting the predicted signal from the original signal. It is then quantized and transmitted. In order to avoid side transmission of the prediction and quantization parameters, a technique called backwards adaptation is used, which relies on the transmitted/received signal to reconstruct these parameters. This entails the predictor being part of a feedback loop, at least in the encoder, which opens up the possibility of using tools and methods from feedback control in the design of adaptive speech coders