1. A system for decoding compressed data, operatively connectable to a length equalizing circuit to receive therefrom data for independent and correlated elements and relative distance data therefrom, comprising: a memory for storing reference data for a reference element; a first register, operatively connected to said memory, for storing and passing therethrough the reference data; a second register, operatively connectable to the length equalizing circuit, for storing and passing therethrough the relative distance data; an addition/subtraction circuit, operatively connected to said first and second registers, for generating an address of a needed element in dependence upon the reference element data and the relative distance data; a third register, operatively connected to said addition/subtraction circuit and said memory, for storing and passing therethrough the address of the needed element; a multiplexer, operatively connected to said memory, said first register and said third register, and operatively connectable to the length equalizing circuit, for multiplexing between said memory and said third register in dependence upon the data for the independent and correlated elements; a comparator, operatively connected to said third register and said first register, for generating a greater than signal in dependence upon the reference data and the address of the needed element; a coincidence circuit, operatively connectable to the length equalizing circuit to receive the data for the independent and correlated elements, for generating a coincidence signal; an AND circuit, operatively connected to said coincidence circuit and said comparator, for generating an output signal in dependence upon the coincidence signal and the greater than signal; an address reading-out circuit, operatively connected to said coincidence circuit, said AND circuit and said memory, and operatively connectable to the length equalizing circuit, for controlling the reading out of the data concerning color change elements from said memory in dependence upon the output signal and the data for the independent and correlated elements and for generating data for a preceding element, said coincidence signal being generated in dependence upon the data for the independent and correlated elements and the data for the preceding element; and an address writing-in circuit, operatively connected to said memory and operatively connectable to the length equalizing circuit, for controlling the writing of data concerning color change elements into said memory in dependence upon the data for the independent element.