The 2 oscillator circuits beneath are well suited for employing crystal oscillators in series or parallel method: Higher-repetition-amount and high-electricity picosecond regenerative amplifier based on an individual bulk Nd:GdVO4 crystal A timing reference incorporating just one-crystal-silicon micromechanical resonator with an outstanding variable of bigger than a million in additio... https://www.hxcrystals.com/seokeywords/bulk-crystal-oscillator.html