The 2 oscillator circuits beneath are well suited for working with crystal oscillators in series or parallel method: Significant-repetition-price and large-electricity picosecond regenerative amplifier dependant on just one bulk Nd:GdVO4 crystal A timing reference incorporating a single-crystal-silicon micromechanical resonator with a quality issue of more substantial than a million and https://www.hxcrystals.com/seokeywords/bulk-crystal-oscillator.html