DIGITAL FILTER AND NYQUIST POINT RETRIEVING METHOD

摘要

PURPOSE: To miniaturize and make a device light in weight by thinning the prescribed range of the calculation of the evaluation value in a Nyquist point retrieving without performing a tap calculation for the prescribed number of delay elements. ;CONSTITUTION: By the delay elements 1, 2 and 3,... of serial connection, a multiplier 4 and an adder 5, a non-recursive digital filter is composed. The multiplier 4 is provided for every three delay elements, for instance, thins the tap calculation for a filtering and reduces arithmatic amount per unit time. But, since the data after the filter passes is outputted for every delay time TM per delay element, the sampling period for the calculation of the evaluation value in retrieval of a Nyquist point can be set to be short. Thus, the accuracy of the estimation of a Nyquist point is improved. While an evaluation value Ws is apart from a prescribed value Pj, the execution of the calculation of the evaluation value is also thinned for every 3TM and further, arithmetic amount per unit time is reduced.;COPYRIGHT: (C)1995,JPO