* Scramble an input stream using an LFSR.  This block works on the LSB only
 * of the input data stream, i.e., on an "unpacked binary" stream, and 
 * produces the same format on its output.
 * \interpolation  拡散符号の周期
 * \param mask     Polynomial mask for LFSR
 * \param seed     Initial shift register contents
 * \param len      Shift register length
 * \ingroup coding_blk
class howto_interp_scrambler_cc : public gr_sync_interpolator
  friend howto_interp_scrambler_cc_sptr howto_make_interp_scrambler_cc (unsigned interpolation, int mask, int seed, int len); 

  gri_float_lfsr d_lfsr;
  howto_interp_scrambler_cc(unsigned interpolation, int mask, int seed, int len);
  //~howto_interp_scrambler_cc ();

  int work (int noutput_items,
	    gr_vector_const_void_star &input_items,
	    gr_vector_void_star &output_items);