Crystal oven

About: Crystal oven is a research topic. Over the lifetime, 955 publications have been published within this topic receiving 10380 citations. The topic is also known as: oven-controlled crystal oscillator & OCXO.

A Fully Integrated Oven Controlled Microelectromechanical Oscillator—Part I: Design and Fabrication

Abstract: This paper, the first of two parts, reports the design and fabrication of a fully integrated oven controlled microelectromechanical oscillator (OCMO). This paper begins by describing the limits on oscillator frequency stability imposed by the thermal drift and electronic properties ( $Q$ , resistance) of both the resonant tank circuit and feedback electronics required to form an electronic oscillator. An OCMO is presented that takes advantage of high thermal isolation and monolithic integration of both micromechanical resonators and electronic circuitry to thermally stabilize or ovenize all the components that comprise an oscillator. This was achieved by developing a processing technique where both silicon-on-insulator complementary metal–oxide–semiconductor (CMOS) circuitry and piezoelectric aluminum nitride, AlN, micromechanical resonators are placed on a suspended platform within a standard CMOS integrated circuit. Operation at microscale sizes achieves high thermal resistances ( $\sim 10~^{\circ }\text{C}$ /mW), and hence thermal stabilization of the oscillators at very low-power levels when compared with the state-of-the-art ovenized crystal oscillators, OCXO. A constant resistance feedback circuit is presented that incorporates on platform resistive heaters and temperature sensors to both measure and stabilize the platform temperature. The limits on temperature stability of the OCMO platform and oscillator frequency imposed by the gain of the constant resistance feedback loop, placement of the heater and temperature sensing resistors, as well as platform radiative and convective heat losses are investigated.[2015-0035]

Variable frequency cavity resonator oscillator

Abstract: This invention relates to an electrical apparatus and particularly to an ultra high frequency oscillator whose frequency output may be varied over a limited range without substantial change in power. In systems operating at ultra-high frequency, it is customary to use cavity resonators with...

Quartz crystal resonator tuning control apparatus

Abstract: A quartz crystal resonator tuning plating automatic control process utilizing an automatic feedback control circuit in a process loop with the quartz crystal being metal plating tuned in an oscillator circuit. The frequency of the oscillator circuit is mixed with a reference frequency and the difference frequency is converted to dc applied to an RC circuit connected to a power amplifier for developing an exponential power output response from the power amplifier that melts and vaporizes plating metal (such as gold) in a vacuum chamber. This results in the plating rate on the quartz crystal being tuned processed tapering off from a much higher rate to a very low plating rate as the desired tuned frequency is approached. Minimum power level and shutoff controls are provided for the power amplifier in attaining desired levels of product frequency adjustment and plating cutoff.

A High Precision Standard of Frequency

Abstract: A new standard of frequency is described in which three 100,000-cycle quartz crystal-controlled oscillators of very high constancy are employed. These are interchecked automatically and continuously with a precision of about one part in one hundred million. They are checked daily in terms of radio time signals by the usual method employing a clock controlled by current maintained at a sub-multiple of the crystal frequency. Specially shaped crystals are used which have been adjusted to have temperature coefficients less than 0.0001 per cent per degree C.

1/f Frequency Fluctuation of a Quartz Crystal Oscillator and Temperature Fluctuation

Abstract: 1 SUMMARY Frequency fluctuations of 5-m~ 5th-overtone plano-convex, AT-cut and IT-cut, quartz crystal oscillators, held in a temperature-stabilized oven, were measured with reference to a CS oscillator (HP 5061A); temperature fluctuations were measured simultaneously using a Pt resistor The power spectral density of the temperature fluctuation was proportional to l/f2 , where f is Fourier frequency The power spectral density of the frequency fluctuation was separat d into three parts; one being proportional to l/>, one to l/f and the third being frequency independent The l/f part and the frequency independent part were in quantitative agreement with the power spectral density estimated from the temperature fluctuation A coherence function between the frequency and temperature fluctuations was calculated The frequency fluctuation is correlated with the temperature fluctuation in the l/$ and frequency independent regions However, the coherence is lower in the range where the l/f spectrum is observed The observed l/f fluctuation is larger than the instrumentation noise, and hence is not electric noise but is attributed to the frequency fluctuation itself