14 This is generated by the 1/2 AWGN code (5 7) operated twice, ie,
15 (xk+1 xki) [xk-1 xk-2] -> [xk+1 xki].
16 We also puncture the first (MSB) bit.
17 This code is worse than awgn2o3_4_msbG and slightly worse than
18 awgn2o3_4, BUT seems to be a good innner code for sctcm (with 8PSK natural).
27 output before puncturing:
34 output after punturing the MSB: