The 2 oscillator circuits below are appropriate for using crystal oscillators in sequence or parallel mode: Substantial-repetition-rate and large-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 one million along with a resonant https://www.hxcrystals.com/seokeywords/bulk-crystal-oscillator.html