公开(公告)号：SG45378A1

公开(公告)日：1998-01-16

申请号：SG1996005250

申请日：1989-06-08

Applicant: IBM

Inventor： CHEVION DAN SAMUEL ,  KARNIN EHUD DOV ,  WALACH EUGENIUSZ

IPC: H03M7/40

Abstract: An improved method is disclosed for generating a compressed representation of a source data string each symbol of which is taken from a finite set of m + 1 symbols, a0 to am . 'The method is based on an arithmetic coding procedure wherein the compressed representation is recursively generated as successive sub-intervals within a predetermined interval. The width of each sub-interval is theoretically equal to the width of the previous sub-interval multiplied by the probability of the current symbol. The improvement is achieved by approximating the width of the previous sub-interval so that the approximation can be obtained by a single shift and add operation using a suitable shift register.