| 摘要 |
<p>PURPOSE:To shorten processing time end also to make it possible to use IC that provides low-speed, low-power-consumption operation, by prescribing the prediction coefficient of prediction DPCM of higher order. CONSTITUTION:Among coefficients of prediction function P(Z) (formula I) shown by Z transform, coefficient A1 of Z<-1> is set to zero. Then, coefficient A2 of Z<-2> takes a number given by A2=+ or -2 + or -2<m>+ or -2<n> (where l, m are integers - or infinity ) expressed by the sum of and difference between power exponents of ''2''. Thus, multiplication of prediction coefficients is replaced by a place shift, addition and subtraction. Thus, the prediction coefficient is prescribed, so that the allowable time of the coding loop of DPCM can be equalized to two sampling periods. Further, calculation of prediction coefficient A2 by prediction device 205 uses an adder- subtracter without using a multiplier, shortening the processing time. Additionally, the circuit can be formed of low-speed, low-power-consumption IC.</p> |
