Patent ID: 6411231
Filing Date: 2002-06-25
Classification: H03M

Abstract:
A coding method comprising:determining symbols in an input data signal, counting occurrences of respective symbols, setting a plurality of probability thresholds that include integer powers of one-half (2âˆ’N), each adjacent pair of probability thresholds determining a respective probability interval, setting a probability representation value between the probability thresholds for each respective probability interval, determining the probability representation value that approximates an occurrence probability of the symbols based on counted occurrences of respective symbols, in binary form, by iteratively shifting by one bit the counted occurrences of one of the symbols and comparing, after each shifting by one bit, shifted counted occurrences for the one of the symbols to total counted occurrences for all symbols until the shifted counted occurrences at least equals the total counted occurrences, and selecting the probability representation value corresponding to the probability interval having a threshold of 2âˆ’N, where N is the number of bits of the counted occurrences of the symbol shifted until the shifted counted occurrences at least equals the total counted occurrences, whereby the probability representation value is determined without arithmetic division, and coding the symbol based on the probability representation value.