I was referring to a publication on BCH codes in GF(64) (http://ipnpr.jpl.nasa.gov/progress_report2/42-38/38O.PDF) where I noticed that the Parity Check Matrix (attached image) that they have derived is at first glance different from a parity check matrix of a standard (63, 56) BCH code.
My question is: How has this Parity Check Matrix been derived?
