| 摘要 |
PURPOSE:To extract a clock signal corresponding to a transmission frequency from a burst data signal itself even when the burst signal of unkonwn transmission frequency is inputted. CONSTITUTION:A first frequency-voltage value converter 1 converts the transmission frequency (f) of the burst data signal S1 into a voltage value V1, and a voltage controlled oscillator 4 outputs a sampling signal S2 whose frequency nf is (n) (integer)-times as much as the transmission frequency (f) of the signal S1. A frequency-dividing circuit 5 frequency-divides the signal S2 into (n)-number. A second frequency-voltage value converter 2 converts the frequency (f) of a frequency-dividing signal S3 into a voltage value V2. A voltage value comparison circuit 3 compares the voltage value V1 with the voltage value V2, outputs the larger voltage value V3 and controls the frequency of the voltage control- type oscillator 4. A sampling circuit 6 samples the signal S1 by the signal S2, and a change point detection circuit 7 detects the change point of a sampling value signal S4 by using the signal S2. A frequency-dividing counter 8 inputs a change point detection signal S5, counts the sampling signal S2 and outputs the clock signal S6 of the signal S1. |
