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.

Frequency synthesizer module for dual band radio

Abstract: A frequency synthesizer module with temperature compensation of a crystal oscillator circuit (12) frequency controlled by a varactor (14). A module memory (18) contains information characterizing a temperature dependency of a crystal (10) which is applied to the varactor (14) to temperature compensate the crystal (10) in response to a temperature sensor signal. The module includes at least one locked loop circuit (22) including a loop filter (24), at least one associated frequency divider, and a switchable dual band voltage controlled oscillator (26). The crystal oscillator (12) is coupled to the at least one locked loop circuit (22) and the frequency of the crystal (10) is controlled by the memory (18) via the varactor (14) such that a temperature compensated output frequency (28) is provided by the module.

Predicting phase noise in crystal oscillators

Abstract: In order to predict the phase noise in crystal oscillators an enhanced phase-noise model has been built. With this model, the power spectral densities of phase fluctuations can be computed in different points of the oscillator loop. They are calculated from their correlation functions. The resonator-caused noise as well as the amplifier-caused noise are taken into account and distinguished. To validate this enhanced model, the behavior of a batch of 10 MHz quartz crystal oscillators is observed and analyzed. The tested batch has been chosen in a facility production. Their associated resonators have been selected according to the value of their resonant frequency and their motional resistance. Open-loop and closed-loop measurements are given. The phase noise of the overall oscillator working in closed loop is provided by the usual active method. Theoretical and experimental results are compared and discussed

Temperature-compensated crystal oscillator

Abstract: A control voltage for a crystal oscillation circuit is formed by adding two separately generated voltages. One of these voltages is proportionally variable with changes of temperature. The other voltage generally follows the temperature-frequency slope characteristic of the crystal unit. A use of such a control voltage eliminates the requirement for designing specific voltage generator circuits for each respective type of crystal oscillator, thereby enabling a substantial reduction in the cost of manufacture.

Liquid crystal panel driving method, liquid crystal device, and electronic apparatus

Abstract: A liquid crystal panel driving method is provided for optimizing driving conditions by performing temperature compensation without varying the voltage of a driving signal. In the liquid crystal device, based on a temperature detection result by the temperature sensor, a temperature compensating circuit sets the frame frequency of driving signals output from driving circuits to a liquid crystal panel at a low temperature, thereby performing temperature compensation so that the liquid crystal device is operated under a condition in which the dielectric anisotropy of the liquid crystal is substantially flat. In accordance with the fact that the motion of the liquid crystal molecules becomes active at a high temperature, the temperature compensating circuit sets the frame frequency of the driving signals to be high. Concerning the frame frequency, 50 Hz (or 60 Hz) and an integer multiple of that frequency are avoided.

Theory and design of crystal oscillators immune to acceleration: present state of the art

Abstract: Theoretical and experimental results on the acceleration sensitivity of quartz crystal oscillators were consolidated in Filler's benchmark review paper published in the May 1988 Special Issue on Frequency Control, Part II of the IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control. Since that time, a large body of additional work has been produced. This paper reviews those developments from the perspective of oscillator design. Areas of direct interest for oscillator design include equivalent circuit models, oscillator circuit interactions, and vibration compensation techniques, along with a clear and concise summary of tile state-of-the-art in low acceleration sensitivity resonator design.