| 摘要 |
PURPOSE:To cancel variation of phase of reference carrier caused by defective adjustment of modulator, defective pi/2 phase shifter of a demodulator and change with the passage of time by discriminating output of a detector and changing phase of the detector according to compounding output of a discriminator. CONSTITUTION:Input signals are branched into two and applied to a first phase detector 2 and a second phase detector 3. Reference carrier waves are branched into two, and one is supplied to the first phase detector 2 and another is supplied to the second phase detector 3 through a pi/2 phase shifted 4 and a variable phase shifter 6. Output of the detector 2 is binary discriminated by a discriminator 7 and an output signal S11 and an output signal s21 are obtained. Output of the detector 3 is binary discriminated by a discriminator 8, and an output signal S12 and an output signal S22 are obtained. The signal S21 and signal S22 are applied to a phase control signal generator 9. Output of the control signal generator is given to the variable phase shifter 6. Even when phase of reference carrier varies, phase variation corresponding to the phase variation is given to the second phase detector 3 by the variable phase shifter 6, and thereby, output not influenced by the reference carrier is obtained as demodulation output. |
