Conversion apparatus and methods for converting two-out-of-six digital code signals into binary code signals. The numerical value of the positions of the two "1's" in the two-out-of-six code signals are added together, along with a constant, shifted by the value of the position of the leftmost "1." This scheme is implemented by programming a general purpose computer, and by special purpose hardware, both using shift registers and adding circuits.
A system for the condensation of a binary signal sequence and for the reproduction of the condensed signal sequence, in which the same encoding means is used both for the condensation and for the reproduction. In the reproduction mode of operation inverters are connected in series with the input and the output of the encoding means. The two inverters together with the encoding means act as a decoder because such a transformation function is selected for the encoding means at which the inverse transformation function is just the complementary function thereof.
