| 摘要 |
PURPOSE:To select an optimum sampling phase speedily not from a specific repetitive signal, but from a random modulating signal by deciding the distribution of an energy variable at a sampling point. CONSTITUTION:A polyphase phase-modulating signal inputted to the input terminal 1 of a demodulating device is sampled by a sampling circuit 2, the sampled signal is digitized by an A/D converting circuit 3, and a demodulator 4 performs two-axial synchronous detection to obtain a base band signal. This signal is passed through delay circuits 10-1-10-4 to obtain a signal shifting the phase by a period the sampling period of the circuit 2. The sums of the squares of synchronizing components of respective signals and the squares of orthogonal components are calculated by amplitude calculating circuits 11-1-11-4. Counters 13- 1-13-4 compare the calculated values of the circuits 11-1-11-4 with the threshold values set in threshold value circuits 12-1-12-4 to decide whether the output values of the circuits 11-1-11-4 are maximum or not. Then, a decision circuit 14 selects a minimum value among the counters 13-1-13-4 and applies it to a selecting circuit, and a discriminator 6 selects the optimum sampling phase. |
