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Fifty years of progress in quartz crystal frequency standards

The progression of developments in crystal frequency standards is traced through the last half century. The paper emphasizes the underlying technical changes and innovations that have driven the remarkable progress, while keeping in mind the contribution of the great body of information that was already available at the beginning of the period. The paper gives a treatment of the progress of ovenized crystal frequency standards from the early vacuum tube days through implementations using transistors, LSI, and hybrid construction. The progression of TCXO developments is also covered including analog thermistor temperature compensation, digital compensation, and techniques using micro-computers, and self-sensed oscillators.