| 摘要 |
PURPOSE:To make it possible to obtain a multiphase multilevel modulating transmitter with a little distortion generation even if a high output amplifier is used in saturation range, by providing a pre-compensating circuit in front of the high-output amplifier of a digital signal transmitter. CONSTITUTION:Four-phase phase modulators 2 and 3 are driven by two sequences of signals S11 and S12, and S21 and S22. Then, high output amplifier 12 is provided at the output side of modulators 2 and 3, and pre-compensating circuit 11 in front of modulators 2 and 3. Since distortion is compensated by compensating circuit 11 even if high-output amplifier 12 is used in the saturation range, so that the transmitter for the multiphase multilevel modulated signal accompanying amplitude modulation with a little distortion generation can be obtained. |
