Digital Audio Fundamentals 429
Figure 14.14(b) : In addition to the redundancy P on rows, inner redundancy Q is also generated on columns.On replay, the Q code checker will pass on fl ag F if it fi nds an error too large to handle itself. Flags pass throughthe deinterleave process and are used by the outer error correction to identify which symbol in the row needscorrecting with P redundancy. The concept of crossing two codes in this way is called a product code.