| 摘要 |
PURPOSE:To simplify the circuit constitution by constituting the titled circuit of a control circuit for phase modulator, a binary-multivalue converting circuit, an oscillator, an amplitude modulator, and a phase modulator arranged at the pre-stage or the post-stage of the amplitude modulator and applied further with phase modulation by the output of the control circuit for phase modulator. CONSTITUTION:The control circuit for phase modulator, e.g., an EPS control circuit 8 discriminates at which position a binary 4-series digital signal fed to a terminal IN is controlled among 12 phase states. Further, the binary - multi-value converting circuit 10 discriminates to which amplitude state the 2nd path input signal corresponds among three amplitude states. On the other hand, after an output of an oscillator 12 generating a microwave is converted into an amplitude modulation signal by an output from the binary-ternary converting circuit 10 by an amplitude modulator 11 comprising, e.g., a pin diode, the result is fed to the phase modulator, e.g., an EPS 9. Since a control signal from the EPS control circuit 8 is fed to the EPS 9, the amplitude modulation signal is subjected to phase shift further and a 16-value QAM modulation signal with high accuracy is sent from a terminal OUT. Since the signal is modulated directly, the circuit constitution is simplified. |
