摘要 |
The filter comprises weighting function circuits (20,22,24,26) which provide weighted signals to pairs of different delay points (32, 36; 42, 46; 52, (56); (62) 30, 66) of the shift register, ie an arrangement for providing symmetrical weightings about a centre point, resulting in a linear phase characteristic. The filter comprises a number of modules (60), each including a weighting function circuit (22) and a pair of adders (32,36) and delay elements (30,34) which are interconnected to give the filter a "folded" structural characteristic. <IMAGE> |