| 摘要 |
PURPOSE:To reduce the time required for eliminating phase uncertainty by detecting a repulling-in phase in a specific order at all times from a present phase state when a pulling-in phase is transited due to phase slip in a 4-phase PSK demodulator. CONSTITUTION:A signal selecting circuit 7 an output SC of an exclusive OR circuit 5, its inverting output, the 2nd output SB of a control signal generating circuit 1 and its inverting output with an output SD of an initial state detecting circuit 8 to output signals SE, SF. The 2nd output SF of the signal selection circuit 7 and the 1st data input P are inputted to an exclusive OR circuit 2 and the 1st output SE of the signal selection circuit 7 controls a signal replacing circuit 4. If a phase slit takes place, the phase of a reproduced carrier has the highest probability in transiting to an adjacent phase rotated by pi/2 and 3/2pi. Through the use of the characteristic, the time for repulling-in is reduced by detecting the repulling-in phase when the pulling-in phase is transited due to phase slip in the order of pi/2, 3/2pi and pi at all times. |
