| 摘要 |
PURPOSE:To correctly detect an identification point even when much noise is included in an input OQPSK modulation wave by detecting an identification point and a change point of data from the transition of a signal sampled by a double recovered clock for the phase detection waveform. CONSTITUTION:A carrier recovery circuit 1 recovers a reference carrier 17 from an input OQPSK modulation wave 16, outputs the result to an I phase detection circuit 2 and a Q phase detection circuit 3 to apply phase detection to the I phase component and the Q phase component of the modulation wave 16. Detection outputs 18, 19 of the circuits 2, 3 are inputted to a clock recovery circuit 4 to detect a data change point and a double recovered clock 20 having a double frequency is generated to the detection outputs 18, 19. Further, a frequency divider 7 divides the clock 20 by 1/2. Then the detection output 18 is subjected to sample quantization by the clock 20 and sampled by the clock 21 to obtain I phase data 25. Further, Q phase data 26 is obtained from the output 19. |
