Crystal oscillators are loosely divided via the frequency they get the job done at and whether they are essential oscillators—operate in the frequency marked about the can or at even multiples of that (overtone oscillators). Modeling of nonlinear micromechanical resonators and their simulation With all the harmonic‐balance process PDF 中原子或分子的排列具有三维空间的周期性，隔一定的距... https://www.hxcrystals.com/seokeywords/bulk-crystal-oscillator.html