A new runlength limited code for binary asymmetric channels [optical storage]

A novel runlength limited code with code rate 3/4 suitable for write-once optical storage is presented complying with the (α, β, γ, δ)=(1, 2, 7, 7) constraint. For this code, the minimum runlength of zeros is one and the minimum runlength of ones is two. The maximum runlengths of both zeros and ones are restricted to seven. If the (d, k)=(1, 7) code was to be used on the same channel the code rate would be 2/3. thus, an increase of 12% in the data rate and a 12% increase in the detection window have been obtained. The encoder, decoder, power spectrum, and error propagation properties of this code are presented