INTELLIGENCE CODING OF AUDIBLE SIGNAL AND SEQUENCE DEMODULATION OF CODED SIGNAL

摘要

PURPOSE: To improve tones by deciding a tone function value as the function of a frequency based on an irregular standard decided based on the predicted value of each S(i ) of each sample frame and the acutally measured value of S(i ) and evaluating a noise shielding threshold value in each i . CONSTITUTION: A tone standard is decided by constituting equations I and II by a program, and in this case, the differences of the radius (r()) and phase (())of a calculation frame one before and a calculation black two before are indicated by dr and d. Predicted radius and phase for a present frame are calculated by equations III and IV from the dr and the d and previous (r) and , and in this case, and difference signals are appropriately readjusted for a dynamic window. From the values and actually measured value of a present spectrum, the irregular standard (C()) is calculated by the equation V. The noise shielding threshold value is evaluated by a tone function value decided from the irregular standard. Thus, the tones are improved.