| 摘要 |
PURPOSE:To obtain the frequency adjustment stable in the oscillator adjusting the average value of frequency, by changing the rate of timing selecting a plural number of oscillating conditions. CONSTITUTION:The input capacitance or output capacitance of the crystal oscillator 7 is divided into two capacitors 10 and 11 and they are taken respectively as C1 and C2. Further, the switch 12 is inserted between the capacitor C11 and ground as the selection means. The control signal phic is fed to the control input terminal of the switch. When this signal phiC is at a high potential, the switch 12 is turned on, the capacitance at the point A is C1+C2, and the frequency of the oscillator is f1. When the signal phic is at a low potential, the capacitor at the point A is only C1, and the frequency of the oscillator is f2 (f2>F1). When the signal phiC is at a high potential only time 7 in the unit time To, the average value f' of the output frequency of the oscillator can be adjusted by changing the value of 7/T with suitable selection of capacitors C1 and C2. In this case, the value to be changed can be 7 or To or the both. |
