High-frequency voltage-controlled-oscillator for use with inverted-mesa quartz resonators

An oscillator circuit has been developed at Sandia National Laboratories that uses inverted-mesa resonators, in a high-precision VCO application, at frequencies historically dominated by SAW designs. This design incorporates a frequency tripler that provides a 600 MHz output capability using a 200 MHz 3^rd overtone resonator. This design has some advantages over equivalent SAW alternatives: lower power-consumption, superior aging characteristics, linear frequency pulling and low frequency versus temperature sensitivity. The VCO presented demonstrates >+/-60 ppm pullability (0 to 7V control), tuning linearity better than +/-5% with phase noise at 1 kHz <-110 dBc/Hz. This oscillator-tripler exploits the nonlinear characteristics of an emitter-coupled-pair differential amplifier to obtain a high-performance oscillator design