(7,4)码的码字多项式 V(x)=x+x2+1=(x+x+1)2 V2(x)=xVi(x)mod(x'+1=x+x+1 V3(x)=xv2(x)mod(x'+1) x++rtx x(x3+x+1) V4(x)=v3(x)mod(x2+1) +x+ x2(x3+x+ 5(x)=xV4(x)mod(x2+1) rotex x(xtx+ V6(x)=xV5(x)mod(c+l +y-4 x2+x+ +x+ V7(x)=xv6(x)mod(c+1) x6+x5+x=(x3+x2+x)(x3+x+1) Vg(x)=x5+x2+x+1=(x2+1)(x3+x+1) Vo(x)=xv8(x)mod(c+1) x6+x3+x2+x=(x3+x)(x3+x+ Vio()=xvi(x)mod(x'+1) =x4+x3+x2+1=(x+1)(x3+x+1) Vil(r=xvid(x) mod(x +1) x5+x4+x3+x=(x2+x)(x3+x+1) V12(c)=xVii(x) mod(x'+1) =x0+x3+x4+ (x3+x2)(x3+x+1)(７,４)码的码字多项式： V1(x)=x 6+ x 2+1=( x 3+ x+1) 2 V2(x)=xV1( x) mod(x 7+1)=x 3+ x+1 V3(x)=xV2( x) mod(x 7+1) = x 4+ x 2+ x = x ( x 3+ x+1) V4(x)=xV3( x) mod(x 7+1) = x 5+ x 3+ x 2 = x 2 ( x 3+ x+1) V5(x)=xV4( x) mod(x 7+1) = x 6+ x 4+ x 3 = x 3 ( x 3+ x+1) V6(x)=xV5( x) mod(x 7+1) = x 5+ x 4+1 =( x 2+ x+1) ( x 3+ x+1) V7(x)=xV6( x) mod(x 7+1) = x 6+ x 5+x =(x 3 +x2+ x) ( x 3+ x+1) V8(x)=x 5+x 2+x+1=( x 2 +1) ( x 3+ x+1) V9(x)=xV8( x) mod(x 7+1) = x 6+ x 3+ x 2+x =(x 3 +x) ( x 3+ x+1) V10(x)=xV9( x) mod(x 7+1) = x 4+ x 3+ x 2+1 =(x+1) ( x 3+ x+1) V11(x)=xV10( x) mod(x 7+1) = x 5+ x 4+ x 3+x =(x 2 +x) ( x 3+ x+1) V12(x)=xV11( x) mod(x 7+1) = x 6+ x 5+ x 4+x 2 =(x 3 +x2 ) ( x 3+ x+1) x 3+ x+1