JPS5461858A - Digital filter - Google Patents

Abstract

PURPOSE:To reduce the arithmetic amount such as multiplication and addition, by shortening the length of a signal word by using a difference in signal as a new signal. CONSTITUTION:The digital filter circuit consists of delay circuits 4, and 71 to 73, adders 21 to 24, and 81 to 83, multipliers 31 to 35, etc. In this constitution, transfer function H(Z) expressed by equation (1) is calculated by the differentiating circuit composed of delay circuit 71 and adder 81, and Z expressed by equation (2) is by multiplier 34. Further, T expressed by (3) is determined by integrating circuit 10 composed of delay circuit 72 and adder 82. Here, the calculation of equation (1) is performed not only for multiplier 34 but also for other multipliers 31 to 35, and the calculation of equation of (3) is done for multiplier 35, and as to other multipliers 31 to 33, integrating circuit 11 is used which consists of delay circuit 73 and adder 83.