| 摘要 |
PURPOSE:To quicken the leading of phase at burst head and to reduce noise at steady state, by widening the band of resonator at transient state of burst head and controlling the band of resonator narower at steady state. CONSTITUTION:At transient state of burst head, an output is appeared at the phase comparison circuit 6, it is converted into a suitable voltage at the drive circuit 7 to control so that the band of resonance circuit 4 is broad. That is, the phase of the resonance circuit 4 is controlled so that it is in agreement with the phase of the resonance circuit 5. When the transient state is finished, the phase of the output of the resonance circuits 4 and 5 is zero, the output of the phase comparison circuit 6 is zero, and control is made that the band width of the resonance circuit 4 can be narrow. As the resonance circuit, in which the band width can be varied, it can be constituted by using variable resistance element of current control such as PIN diode. |
