The 2 oscillator circuits beneath are suitable for working with crystal oscillators in sequence or parallel mode: Higher-repetition-fee and superior-ability picosecond regenerative amplifier depending on only one bulk Nd:GdVO4 crystal A timing reference incorporating only one-crystal-silicon micromechanical resonator with an outstanding aspect of much larger than a million in addition https://www.hxcrystals.com/seokeywords/bulk-crystal-oscillator.html