| 摘要 |
PURPOSE:To reailze both the rationalization of designing and the high stability, by supplementing the voltage control type variable capacity diode, keeping a wide varying range of the frequency until the atom standard is locked and then switching to a narrow frequency control range after locking. CONSTITUTION:Three voltage control type variable capacity diodes D16, 26 and 28 are connected in parallel as the load of crystal oscillator 15. And D16 is controlled as conventional by the output of servo amplifier 11; while D26 and D28 are controlled by oscillator 20 (delivering the long-cycle signal of about 30sec), gate 21, FF group 22 and its outputs 23 and 24 each, and at the same closes gate 21 when the locking signal arrives from amplifier 22. In other words, the locking range is wide since the frequency is scanned over a wide range until the atom standard is locked. And a high frequency stability can be obtained after the atom standard is once locked since the variation of the oscillation due to the change of the control voltage can be reduced. |
