| 摘要 |
PCT No. PCT/IB97/00274 Sec. 371 Date Nov. 14, 1997 Sec. 102(e) Date Nov. 14, 1997 PCT Filed Mar. 20, 1997 PCT Pub. No. WO97/36369 PCT Pub. Date Oct. 2, 1997A Pierce oscillator has been modified to replace the large capacitor with an amplifier element in order to make it more compact. A first amplifier element has a control terminal and a main current path extending between first and second output terminals. A network feeds back the signal at the first output terminal of the first amplifier to the control terminal of the first amplifier element and includes a series-arranged piezoelectric oscillation element. The oscillator also includes a reactive circuit element such as a resonant LC circuit or inductor (herein called an output dipole) coupled to the first output terminal of the first amplifier element and a DC current defining element coupled to the second output terminal of the first amplifier element. The very large capacitor ordinarily required in such a Pierce oscillator to provide a shunt around the DC current defining element at the oscillation frequency is replaced instead by a second amplifier element having a main current path coupled to the second output terminal of the first amplifier element. In a preferred embodiment, positive feedback is provided to the second amplifier element to reduce power consumption and shorten the turn-on transient period.
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