| 摘要 |
PROBLEM TO BE SOLVED: To detect the phase differential of a modulated signal of a PSK system whose number of modulation phases changes in time division with a simple circuit and by the uniform sensitivity. SOLUTION: The received phase of a modulated signal is mapped on a complex plane that is divided into plural signal areas in accordance with the number of modulation phases, phase differential among a reception phrase and plural reference phases corresponding to the largest number of modulation phases are calculated respectively as the distance between a mapping position and a reference straight line by a differential calculating means 22. One on which the reception phase is mapped from plural signal area is judged by an area judgment means 23 and one is selected out of the plural phase differentials by a differential selection means 24 in accordance with this signal area. Since the phase differential is proximately calculated as the distance, the processing is facilitated and, since one is selected out of the plural phase differentials for calculating in accordance with the largest number of modulation phases, the detection sensitivity of the phrase differential is not varied even if the number of modulation phases changes. |
