rotation vector is output on line 116 and combined in rotator 41 with the mapped n msb 39 s on line 38 to form a phase rotated signal optionally phase encoder 37 includes differential phase encoder 118 which encodes the lsb 39 s of the n bit word to develop 1 differential bit this previous differential bit is output on line 119 and combined with the lsb from register 122 in adder 112 and becomes part of the rotation vector 114 rotator 41 performs vector multiplication on the rotation vector on line 116 and the mapped n msb vector word on line 38 to cause a phase rotation or simply a positive negative polarity inversion thus producing the final polarity symmetric signal space constellation used to transmit the information including the additional special marker symbol of the present invention on line 42 in the case of pam the rotator simply inverts the polarity or sign of the pulse amplitude the constellation on line 42 is supplied to scaler 43 scaler 43 multiplies the constellation by a scale function of the data rate and supplies a real number comprising x values on line 47 to tx filter 46 in the case of pam a single real number x is supplied on line 47 to tx filter 46 which may be a simple low pass filter alternatively tx filter 46 may be a hilbert filter the scale function allows a single table to be used to implement the mapper at all data rates tx filter 46 operates on the signal to provide a pam modulated signal on line 49 to digital to analog converter dac 52 in an alternate embodiment of the present invention the scaled constellation on line 47 is modulated using uncoded modulator 48 using a technique such.