  In this letter we consider the ensemble of codes formed by the serial
concatenation of a Hamming code and two accumulate codes. We show that this
ensemble is asymptotically good, in the sense that most codes in the ensemble
have minimum distance growing linearly with the block length. Thus, the
resulting codes achieve high minimum distances with high probability, about
half or more of the minimum distance of a typical random linear code of the
same rate and length in our examples. The proposed codes also show reasonably
good iterative convergence thresholds, which makes them attractive for
applications requiring high code rates and low error rates, such as optical
communications and magnetic recording.
