Crystal oscillators are loosely divided through the frequency they operate at and whether they are elementary oscillators—function within the frequency marked within the can or at even multiples of that (overtone oscillators). Superior-repetition-price and significant-power picosecond regenerative amplifier depending on only one bulk Nd:GdVO4 crystal HTML White paper TI BAW https://www.hxcrystals.com/seokeywords/bulk-crystal-oscillator.html