| 摘要 |
PURPOSE:To convert with a good S/N ratio a nonstandard frequency to a standard frequency which can be inputted to an error expanding device, by using a sampling system phase control loop. CONSTITUTION:A frequency fx to be measured is inputted to a sampling gate 3. On the other hand, to this gate 3, a sampling pulse which has divided an output of a 5MHz voltage control crystal oscillator 1 by a 1/n frequency divider 2 is inputted in advance, and the frequency fx is sampled by this pulse. This sampling output is held by a holding capacitor 4 and becomes a stepwise low frequency signal. It is amplified by a DC amplifier 5, and after that, is fed back to the oscillator 1 through an LPF6. In this way, since a phase control loop consisting of the gate 3 and the oscillator 1 is constituted, the frequency of the oscillator is controlled by an output of the LPF6. An output of a phase synchronizing oscillator is fetched through a buffer amplifier 7 from the oscillator 1. In this way, 5MHz synchronizing with the frequency fx is obtained. |
