| 摘要 |
PURPOSE:To respond to a various kinds of transmission speed of modulation data by varying the frequency of a second VCO(voltage controlled oscillator), and mixing it with the output signal of a first VCO by a mixer. CONSTITUTION:A clock phase error signal extracted by a digital phase error extraction circuit 1 is passed through a loop filter 2, and a D/A converter 3, and the frequency and the phase of the first VCO 4 are controlled by the signal. Also, the second VCO 7 generates a various kinds of frequencies by a frequency control signal inputted from the outside. And the output signals from the first VCO 4 and the second VCO 7 are mixed by the mixer 5. Therefore, the frequency of a regenerating clock signal can be varied arbitrarily by varying the oscillation frequency of the second VCO 7 by an external frequency control signal. In such a way, it is possible to respond to the transmission speed of all the modulation data by one circuit. |
