| 摘要 |
PURPOSE:To obtain a high speed type CMOS piezoelectric oscillator for an overtone by connecting a resistance of <=10kOMEGA between an input and an output of a CMOS integrated circuit, suppressing a fundamental wave of a piezoelectric vibrator, and executing an oscillation by an overtone frequency. CONSTITUTION:Between an input and an output of a CMOS integrated circuit 1, a resistance 4 for bias and a crystal resonator 5 which is excited by a tertiary overtone are connected in parallel, and capacitors 6, 7 are connected to both terminal sides of the crystal resonator 5 and grounded to the earth potential. When the capacitors 6, 7 are set to a prescribed value of 8pF and the resistance 4 has been made variable, when a resistance value has been set to 1.6kOMEGA, an oscillation of 70MHz starts to be stabilized, and when exceeding 6.8kOMEGA, an oscillation stable area is eliminated. In the same way, when the capacitors 6, 7 have been set to 27pF, an oscillation is executed by 15-22MHz in 6.8kOMEGA. Accordingly, the smaller a value of the resistance 4 is made, the higher frequency is obtained for an oscillation area,s and when executing an oscillation by a tertiary overtone frequency exceeding 20MHz, the capacity of the capacitor is made constant and the resistance value is set to <=about 7kOMEGA.
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