ABSTRACT
In this work, we present a variable-frequency quartz crystal oscillator that is able to oscillate at LC resonance under frequency locking of a quartz crystal resonance, with the frequency tuning realized by variable-capacitance diodes. This circuit shows a steep transition between LC oscillation modes to quartz crystal double-resonance, which shows a characteristic change in the oscillation frequency. Control voltage of this diode is precisely adjusted from the low side to higher values and conversely in the vicinity of the oscillation mode transition. The transition of the oscillation modes is experimentally demonstrated and compared with an algebraic analysis.
ABSTRACT
In this work, our goal is to develop a voltage-controlled variable-frequency quartz crystal oscillator with narrowband response, wide, variable frequency range and the capacity to oscillate across the series resonance frequency using a four-segment configuration of a quartz crystal oscillator. In conventional quartz oscillators, the quartz resonator is inserted in the feedback loop between the input and the output of the active circuit, providing sufficient gain and the phase relation. In the oscillator developed here, the quartz crystal resonator is inserted between the loop circuit and the ground potential. The performance of the voltage-controlled variable-frequency oscillator is demonstrated across the series resonance frequency.
Subject(s)
Electronics/instrumentation , Micro-Electrical-Mechanical Systems/instrumentation , Oscillometry/instrumentation , Quartz , Equipment Design , Equipment Failure AnalysisABSTRACT
In this work we propose a novel circuit design: a double-resonance oscillator. Its oscillation shows two oscillation modes: frequency locking to the quartz crystal resonance and LC resonance oscillation. Transition of the oscillation mode and the strength of oscillation are analyzed and reviewed for the fundamental mode in comparison with a Colpitts oscillator. The experimental results support the estimates of negative resistance for the double-resonance oscillator compared with the LC oscillator.
