| 摘要 |
PURPOSE:To prevent an error voltage from being generated in a block having no change in a regenerative signal and to improve stability and following-up ability for clock reproduction by comparing regenerative clocks each other in this block. CONSTITUTION:A selecting circuit 1 discovers the change point of the regenerative signal from '0' to '1' or from '1' to '0' and when there is the change point, the regenerative signal is transmitted at this point. On the other hand, when there is no change point, the circuit 1 transmits the regenerative clock from a voltage control circuit 4. As the result, when there is the change in the regenerative signal, a phase frequency comparator 2 compares the regenerative clock with a signal to compare the phase and the frequency and generates the error voltage required for reproducing the clock. Reversely, when there is no change, no useless error voltage is generated since the phases and frequencies of the regenerative clocks are compared each other. |
