A converted digital signal is provided in an NRZI (non-return to zero, inverted) code with a zero DC component and with a maximum predetermined number of bits between level transitions in the signal. The base digital signal is divided into m-bit base words, each of which is then converted into an n bit converted code word to form a converted digital signal suitable for recording. The n-bit converted code word is selected from a plurality of primary combinations or code words having a DC component substantially equal to zero when NRZI-coded and a plurality of secondary combinations or code words having a DC component with an absolute value of two when NRZI-coded. A variance of the DSV (digital sum variation) of each primary combination when NRZI-coded and a polarity of the DC component of each secondary combination when NRZI-coded are altered in response to the DSV at the exit of the preceding converted digital signal.