1. A method of scrambling successive, thermometer coded binary input data words comprising N bits into corresponding successive output data words also comprising N bits, characterized in that, if the number of bits of one binary value has increased from one input data word to the next, bits of said one binary value are maintained in positions in the corresponding output data word where the previous output data word had bits of said one binary value, and the remaining bits of said one binary value are randomized to positions in the corresponding output data word where the previous output data word had bits of the other binary value, whereby the number of positions to be altered in a transition from one output data word to the next is minimized.