Patent ID: 7098816

Claim:
A method of quantizing a signal in a digital signal processing system, comprising the steps of: receiving an input signal; comparing the input signal and a current predicted signal using a comparison unit, the comparison unit comprising a subtractor for computing a deviation value by subtracting between the current predicted signal and the input signal; quantizing the input signal using a tri-state quantizer into a current quantized value selected from a set of three different quantized values including a low value, a middle value, and a high value, the selection of the value being based on a result of comparing the input signal and the current predicted signal such that the current quantized value is selected to be: a. the low value of the three different quantized values when the deviation value is below a minimum threshold; b. the middle value of the three different quantized values when the deviation value is greater or equal to the minimum threshold but smaller or equal to a maximum threshold; or c. the high value of the three different quantized values when the deviation value is greater than the maximum threshold; generating from the current quantized value an output signal representative of the input signal; determining a next predicted signal for a subsequent sampling period; feeding the next predicted signal back to the comparison unit; and dynamically adjusting a quantization step size using a step-size controller, the adjusting being at least partially based on a quantization history including a quantized value of at least one sampling period, the quantization step size being defined by a difference between the maximum threshold and the minimum threshold.