The 2 oscillator circuits below are suited to using crystal oscillators in sequence or parallel mode: Significant-repetition-rate and substantial-ability picosecond regenerative amplifier according to one bulk Nd:GdVO4 crystal A timing reference incorporating only one-crystal-silicon micromechanical resonator with a quality element of much larger than a million along with a resonant https://www.hxcrystals.com/seokeywords/bulk-crystal-oscillator.html