The Standardization of Quartz-Crystal Units

Quartz-crystal units have been thrust into enormous production before their engineering treatment as circuit elements has become formalized. As a result, crystals are specified in terms of the desired performance of the set which is to use them rather than in terms of their own properties. The intrinsic properties of crystal units form the ideal basis for their specification. When it becomes the practice to use the circuit properties of crystal units, when convenient instruments for measuring the impedance of crystal units at the frequency of oscillation are available, and when the formal treatment of oscillator-circuit design is extended to include crystal-controlled types, there will naturally follow the convenient cataloging of crystal units and their properties in conventional circuit terms, the reduction in the number of crystal types, and standardization of a few types. This will reduce the use of quartz-crystal units in radio circuits to an engineering basis where ordinary circuit-design methods will apply and will make unnecessary the "cut-and-try" procedures which are today's common practice.