| 摘要 |
PCT No. PCT/JP92/00932 Sec. 371 Date May 28, 1993 Sec. 102(e) Date May 28, 1993 PCT Filed Jul. 20, 1992 PCT Pub. No. WO93/03545 PCT Pub. Date Feb. 18, 1993.The frequency control and phase control of a voltage-controlled oscillator (50) of a phase-locked loop (100) comprise two current paths. The frequency control system comprises a filter (75) that converts pulse output current (i1) of a charge pump (70) generated by phase error signals (X1, X2) to a DC voltage, and a resistor (R1 or R2) that converts that voltage to DC current (i3), and the phase control system comprises a charge pump (80) that generates a pulse output current (i2) using the phase error signals (X1, X2). The frequency and phase of the oscillator output (VOUT) of the voltage-controlled oscillator (50) is controlled by a composite current i4, which is the sum of the DC current (i3) and the output current i2. Since it is possible to make the natural angular frequency proportional to the data transfer rate while the damping factor remains unchanged, by changing the value of the currents (i3, i2) through the switching of switches (SW1, SW2) when the data transfer rate of the input signal (SIN) changes, a phase-locking characteristic can be realized that accommodates a wide range of data transfer rates.
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