BAND LIMITATION INTERPOLATING FILTER

摘要

PURPOSE:To shorten the calculation time for finding a tap coefficient and to vary band characteristics of a filter only varying intervals of table reference by employing a method for referring tables which contain impulse responses. CONSTITUTION:An image memory 5 outputs 2I'+1 image data Pi' based upon a specified address io as their center. The image data Pi' outputted by the image memory 5 are delayed by an FIFO 12 by the time required to find the coefficient of a filter. The tables T-1'-TI ' store discrete data which are obtained by dividing the data into Tx' up to the 1st zero point of a Sinc function and sampling them with 1/2Tx'. Tap coefficients of filters obtained by referring to the tables and said image data Pi' are multiplied by multiplexers Mo', and M-I-MI ' respectively and their sum is calculated by an adder Ao to obtain an output image qmo, which is outputted to an output terminal 2.