| 摘要 |
PURPOSE:To improve the deterioration in an error ratio by providing a variable phase shifter controlled by using an error signal from the second or first discrimination circuits between the second hybrid circuit and the first or second detector and compensating the dislocation of the phase difference between two reproducing carriers with a variable phase shifter. CONSTITUTION:Since the phase of a reproducing carrier inputted to a detector 3 is dislocated by a temperature change, the dislocation is compensated by a variable phase shifter 8 controlled by a control circuit 9. Namely, error signals I4 and I5 from a discrimination circuit 5 are applied to an exclusive OR circuit EX-OR91, an EX-OR is obtained, and the signals are applied through an integrator 92 and an A/D converter 93 to a microprocessor 94. The control signal generated by using the method of perturbation is applied through a D/A converter 95 to a variable resistor Rv. Then, the reverse bias voltage of a variable capacity diode 81 is changed by DELTAV, the capacity of the diode is changed by DELTAC, the phase of the reproducing carrier applied to the detector 3 is shifted by DELTAphi, the phase dislocation from 90 deg. is improved and the deterioration in a code error ratio can be improved. |
