A comparison of frequency pullability in oscillators using a single AT-cut quartz crystal and those using two single AT-cut crystals connected in parallel with a series load capacitance or series load capacitance or series load inductance

摘要

This paper presents a comparison of frequency pullability in oscillators using asingle AT-cut crystal and those using two single AT-cut crystals connected in paralleloperated with a series load capacitance or series load inductance at fundamental frequenciesof 4, 10 and 19 MHz. Pullability describes how the operating frequency may be changed byvarying the load capacitance. The paper also gives impedance circuits for both single- anddual-crystal units. The experiment results show that the new approach using two singlequartz crystals connected in parallel increases the frequency pulling range by 30-200% pending on the type of oscillator. Also given is the crystal frequency stability at thesethree frequencies.