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 Measurement Technique for Determination of Frequency vs Acceleration Characteristics of Quartz Crystal Units

Abstract: : A computer-controlled g-sensitivity measuring apparatus has been assembled and used to screen 100 MHz AT-cut crystal units for any manufacturing defect. This apparatus obtains the g-sensitivity vs. acceleration characteristic of a crystal unit alone in less than 100 seconds in a given direction. The basic equations governing computation of g-sensitivity from the measured data can be used to determine a new set of component requirements for the apparatus when measuring different crystal types to a specified g-sensitivity level. It has already been shown that measurement of g-sensitivity levels less than 10 to the minus 11th power is possible for 100 MHz quartz crystal units. The described g-sensitivity measurement technique can be used to study mechanical resonance properties of crystal mounting and packaging schemes, simply screen defective crystal units, or investigate interfering modes of low frequency mechanical resonances of the crystal plate and supporting systems after a simple modification of the measurement software.

New digital compensation technique for the design of a microcomputer compensated crystal oscillator

Abstract: The study of the stability of frequency sources is a matter of major interest due to the evolution of communication and instrumentation systems resulting in increasing the number of channels in a limited spectrum, and reducing size and power consumption. The paper relates laboratory experiences that explain the behavior versus temperature of thickness-mode quartz crystal resonators (AT- and SC-cut crystals) that are applied to the control of frequency sources, and the performance of digital compensation techniques. Prototypes of microcomputer-compensated crystal oscillators (MCXO's) have been developed to compare the compensation performance using the resonator as the temperature sensor against the use of an external sensor and verify the reduction of compensation errors due to thermal lags and hysteresis. The design of a CMOS integrated circuit for the MCXO is also included. A frequency correction method that does not modify the crystal resonance has been implemented in the circuit. This allows sensing of the temperature by means of the crystal and improving its long-term stability (aging). A new frequency comparator is also introduced. Its aim is to obtain the difference between two very close frequencies at its output, without being affected by the phase variations that the new frequency correction method and the digital circuit introduce. This detector has been implemented to get a high-resolution thermometric frequency and to realize a frequency-locked loop that includes a crystal controlled local oscillator, allowing the use of the MCXO as a good short-term stability source. >

Temperature sensitive oscillator

Abstract: An oscillator circuit for sensing and indicating temperature by changing oscillator frequency with temperature comprises a programmable operational amplifier which is operated on the roll-off portion of its gain versus frequency curve and has its output directly connected to the inverting input to place the amplifier in a follower configuration Its output is also connected to the non-inverting input by a capacitor with a crystal or other tuned circuit also being connected to the non-inverting input A resistor is connected to the program input of the amplifier to produce a given set current at a given temperature, the set current varying with temperature As the set current changes, the gain-bandwidth of the amplifier changes and, in turn, the reflected capacitance across the crystal changes, thereby providing the desired change in oscillator frequency by pulling the crystal There is no requirement that a crystal employed with this circuit display either a linear frequency change with temperature or a substantial frequency change with temperature