Crystal oscillators are loosely divided with the frequency they get the job done at and whether they are essential oscillators—work at the frequency marked within the can or at even multiples of that (overtone oscillators). As you are able to see in the graph underneath, crystals have two resonant details. https://classifylist.com/story20739545/how-much-you-need-to-expect-you-ll-pay-for-a-good-bulk-crystal-oscillator