| 摘要 |
PURPOSE:To improve the DC level control characteristic of a signal with a simple constitution by generating a data signal and an error signal respectively by using only respective signals in I channel system and Q channel system in order to control the DC level for a remodulated signal. CONSTITUTION:A reception signal 101 modulated based on SS-QAM system inputted to an input terminal 6 is inputted to a QAM demodulator 1 where it is subjected to synchronization detection, so that an I-channel demodulated signal 102 and a Q-channel demodulated signal 102' that cross with each other orthogonally are outputted. The signals 102, 102' are respectively inputted to DC level controller 2, 2'. Signal converters 11, 11' respectively process a signal so that the amplitude level value of a signal in response to a signal point in SS-QAM system comes equal to the amplitude level value of a signal in response to correspondent signal point in C-QAM system, and the amplitude level value of a signal in response to a signal point disposed in outermost position in SS- QAM system that cannot be correspondent to the signal point disposition in the C-QAM system comes equal to that of a signal in response to a signal point disposed in the outermost position in the C-QAM system. |
