Conversion of three-place binary PCM code word - replaces ternary pair in some cases by spare auxiliary ternary pair

摘要

The code word is converted into a two-place ternary PCM code word. Eight different ternary code words are allocated to eight possible different binary words. Two ternary words from a pair of equal digits. The third pair of at first unused equal digits serves as an additional pair. Any of the two pairs, designated as the first, is replaced by the additional pair when the first pair consecutively appears a second time, and the end digit of the preceding ternary word is different from the digits of the additional pair. The second pair is replaced by the first when it would have appeared for the second time, and the end digit of the preceding ternary word is the same as the digits in the second word.