The 2 oscillator circuits under are suitable for employing crystal oscillators in series or parallel method: Large-repetition-amount and high-electrical power picosecond regenerative amplifier dependant on just one bulk Nd:GdVO4 crystal A timing reference incorporating just one-crystal-silicon micromechanical resonator with an outstanding aspect of larger than a million along with a https://www.hxcrystals.com/seokeywords/bulk-crystal-oscillator.html