Combining ECC with modulation: Performance comparisons

The author describes a technique for combining error-correcting codes (ECC) with block-type modulation codes. Its performance is analyzed with respect to the traditional method in magnetic recording, which involves the concatenation of an ECC with a convolutional modulation code. Conditions under which the new method is superior to the concatenation scheme are established. In particular, the performance with respect to the (1, 7) and (2, 7) modulation constraints is analyzed. It is concluded that the new construction performs better in a noisy channel dominated by random errors. Cases in which relaxing the constraint k allows better global rates are also studied.