Book excerpt: The purpose of the program was to compile a quartz crystal oscillator design handbook to facilitate and systematize the design of quartz crystal oscillators, to eliminate crystal unit misapplications, to reduce design time and costs, and to increase the reliability of operation. The handbook is specifically directed at the wide operating temperature range, medium stability crystal oscillator prevalent in many types of communications equipment, although the basic design principles also apply to temperature controlled oscillators. In addition, the program was concerned with obtaining oscillator performance data for inclusion in the handbook.