| 摘要 |
PROBLEM TO BE SOLVED: To determine the oscillation frequency of a current-controlled oscillation circuit with input/output characteristics of a voltage-current converting circuit and to use its linear part by receiving a voltage value as the result of phase comparison by a filter circuit, converting a generated phase compensation voltage value into a current, and driving the current-controlled oscillation circuit. SOLUTION: A frequency comparing circuit 13 compares the frequency of a data stream with that of a clock CLK and inputs a comparison results corresponding to the error between a phase loop side and a frequency loop side to the voltage-current converting circuits 5a and 5b through phase compensating filters 15a and 15b, and it is converted here into a current value, which is inputted to a current adding circuit 6. Here, the added input current is inputted as a control current to the current- controlled oscillation circuit 7, whose oscillation frequency is controlled according to the value of the control current to generate a clock CLK of specific frequency. Consequently, the linear part of input characteristics from a fine current to a large current is used to linearly control the oscillation frequency of the current-controlled oscillation circuit 7 over a wide band. |
