| 摘要 |
PURPOSE:To increase the multilevel number and to improve the frequency use rate by converting the signal point arrangement of transmission data from a rectangular grating to a honeycomb in a modulator. CONSTITUTION:The signal point arrangement of in-phase data and quadrature data is converted from a rectangular grating to a honeycomb by a signal point arrangement converting part 101, and data is sent to a transmission line 300 after quadrature amplitude modulation in a quadrature amplitude modulating part 102. A multilevel quadrature amplitude modulated and demodulated QAM is detected by a synchronous detecting part 201 to obtain an in-phase signal Xb and a quadrature signal Yb, and the operation of conversion from rectangular coordinate axes to three coordinate axes connecting signal points adjacent to one another in the honeycomb signal point arrangement is performed by a coordinate transforming part 202 with respect to these signals, and three coordinate transformation output signals X, U, and V corresponding to respective coordinate axes are obtained. Signal points of these output signals X, U, and V are discriminated by a signal discriminating part 203 to output output data corresponing to signal points. |
