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.

Method and apparatus for frequency stabilizing oscillators

Abstract: Frequency stabilization of an oscillator by compensating for slow frequency variations due to ambient temperature variations is achieved by diverting a fraction of the oscillator output to a waveguide line section having a coefficient of thermal expansion/° C which is greater than the coefficient of relative frequency drift/° C of the oscillator comprising, in sequence, a variable attenuator and a movable short. The variable attenuator is used to primarily adjust the amplitude of the diverted signal by one-half the desired amount preferably without varying the phase of the diverted signal. The movable short is primarily used for signal phase adjustment while simultaneously reflecting the attenuated signal back through the attenuator and towards the oscillator output. Temperature variations which cause impedance changes in the oscillator, and in turn frequency changes at the output thereof, similarly affect the components of the divergent waveguide line section to produce reactive load variations therein of corresponding magnitude and opposite sign to the impedance changes in the oscillator.

Wide-range temperature compensation by addition of two crystal-resonator frequencies: practical results with quartz and LiTaO3

Abstract: Practical results are presented on a novel method for compensating the frequency drift of crystal oscillators. The digital summing of a 300 kHz quartz and a 200 kHz LiTaO3 crystal resonator results in a sum frequency whose temperature drift is 10 times smaller than the drift of quartz or LiTaO3.

Method of calibrating PLL frequency synthesizers to precise frequencies with low tolerance crystals in their master reference oscillators

Abstract: A frequency tracking circuit and method comprising a master crystal oscillator circuit is used for frequency tracking between a handset and a base station comprising a calibration subsystem for taking a temperature measurement, a reference control circuit for determining a numerical value needed to align a handset frequency with a base station frequency, an adder for adding the numerical value to a previous numerical value determined by the reference control circuit, a latch for latching the output of the adder, and a low precision master crystal oscillator for clocking the frequency of the latch. The most significant bit from the latch is input into a phase/frequency detector for forcing a voltage controlled oscillator to track a desired frequency.

Examination for realization of a high precision crystal sensor

Abstract: The frequency stability of a crystal sensor in liquid is influenced by a decrease in Q value. Also, the frequency stability is influenced by the water pressure, liquid temperature, and etc. this paper shows a new method of realizing a highly precise crystal sensor by using two crystal sensors for the purpose of solving the above mentioned problem. In conclusion, it has been verified that a crystal resonator having two pairs of electrodes on one AT-cut crystal blank can be used for sensors in liquid for various applications.

Development status of the microcomputer compensated crystal oscillator

Abstract: The design of the MCXO eliminates the three primary obstacles to stability of the conventional temperature compensated crystal oscillator (TCXO). These are: (1) errors in measuring the crystal temperature; (2) use of a fundamental mode AT instead of an overtone SC cut crystal; and, (3) hysteresis and aging associated with pulling the crystal. As a result, the MCXO achieves about 30 times better stability than the best TCXOs. In this paper we review the MCXO design technology, describe the Q-Tech MCXO, QT2001, and describe some future developments.