Forty-years history of development and up-to-date status of industrial types of internally heated quartz resonators (IHQRs) and oscillators on their basis

In this article forty-years histroy of development and up-to-date status of industrial types of internally heated quartz resonators (IHORs) and oscillators are described. Each model has its own advantages. The problems like change in significant temperature gradients, breakage in a relatively short time vacuum were not overcome by IHQR with a bimetallic switch and with a film heater and a temperature sensor on the quartz blank. The use of a glue to mount the IC on the holder led to a failure in keeping stable vacuum in the IHQR´s enclosure and, consequently, - to the significant increase of long-term power consumption and worsening of frequency stability. So this idea was not developed and, all the more, was not realized in industrial manufacturing. At present, the works on the modification with high resistance against vibration and shocks are in progress; this will extend the forthcoming applications. Further improvement of the IHQR design with combined heater assumes reduction of sizes with sustaining high frequency stability. Research and development of improved devices are continued; new models are put into production line.