| 摘要 |
A crystal controlled square wave oscillator requiring a minimum number of components, exhibiting high frequency stability, and operating at substantially a 50% duty cycle. A quartz crystal dual monolithic resonator is provided having a pair of signal electrodes and a reference electrode. The resonator is capable of oscillating in symmetric and anti-symmetric modes, points of minimum attenuation, the symmetric mode exhibiting a 180 DEG phase shift, and the anti-symmetric mode exhibiting a phase shift of 0 DEG . An integrated circuit logic gate is connected between the signal electrodes, the logic gate being of the type having low input and output impedances so as not to degrade the Q of the resonator. The logic gate provides a phase shift of 180 DEG or 0 DEG causing the resonator to oscillate in its symmetric or anti-symmetric modes, respectively, the gate switching between its two logic levels to produce a square wave output at the frequency of the excited mode.
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