| 摘要 |
PURPOSE:To simplify a circuit and to decrease a cost by constituting two SOM (start of message) detectors and a phase ambiguity correcting device of a large capacity ROM respectively, inputting a phase information signal and a serial signal from a PSK demodulating board by the phase ambiguity correcting device and outputting the serial signal to remove the phase ambiguity. CONSTITUTION:SOM detectors 3 and 4 and a phase ambiguity correcting device 6 are respectively constituted of one large capacity ROM of 64 K bits or above. The removing circuit corrects eight ambiguities to occur at the process of four phase phase demodulation on a demodulating board and reproduces correct data. The correction of ambiguity is controlled by the control signal of a selector in a position ambiguity correcting device 6. For example, a phase detector 5 detects the phase information by analyzing output signals 105 and 106 of the SOM detectors 3 and 4 and outputs three types of pulses for correcting the ambiguity to the selector of the phase ambiguity correcting device 6. Thus, the control signal of the selector comes to be the correct condition and the ambiguity is corrected. |
