The two oscillator circuits underneath are appropriate for utilizing crystal oscillators in series or parallel method: Superior-repetition-charge and substantial-electricity picosecond regenerative amplifier based on just one bulk Nd:GdVO4 crystal A timing reference incorporating an individual-crystal-silicon micromechanical resonator with a high quality variable of larger sized than ... https://www.hxcrystals.com/seokeywords/bulk-crystal-oscillator.html