method and apparatus for constant enveloping curve quadrature quadrature amplitude modulation

摘要

A constant envelope quadrature-quadrature amplitude modulation system limits the data, which will be transmitted, to 4-bit and adds 4-bit parity to make them have a constant envelope in the Q2AM system, which modulates 8-bit in units of 2-bit. The system includes: a constant envelope encoder 52 for adding 4-bit parity to 4-bit input information; four mappers 12 to 15 for respectively generating level signals corresponding to data values of 2-bit among 8-bit data generated by the constant envelope encoder 52; four mixers 16 to 19 for respectively mixing the level signals generated by the four mappers 12 to 15 with different predetermined frequency signals; and adder 20 for adding up the signals generated by the four mixers 16 to 19.