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.

Use of a multiplexed oscillator in a miniaturized electronic nose based on a multichannel quartz crystal microbalance

Abstract: Acoustic sensors are generally known as high-resolution mass-sensitive transducers They are composed of piezoelectric crystal plus at least one layer of chemically interactive material (CIM) deposited on one of their surfaces in order to infer a given chemical sensitivity Electronic noses based on quartz crystal microbalances (QCM) are widely used in volatile organic compounds analysis These multisensor systems typically employ a number of quartzes coated with different CIM having broad and overlapping sensitivity Depending on the number of sensors used and taking into account the electronic units needed to drive them, the total volume of such a system may be considerable In the present work we have shown the possibility of including four different QCM in the same quartz plate in order to reduce the overall space dedicated to the sensors, realizing the so called multichannel quartz crystal microbalance (MQCM) Moreover we have investigated the possibility of using a single oscillator circuit to drive the oscillations for all the four channels of the MQCM The work outlines the advantages of implementing this single oscillator technique in terms of volume reduction, better homogeneity in the sensor array behavior and power saving The overall system comprising the sensor array, the driving oscillator and the electronic interface has been built and successfully tested

Quartz resonator cut to compensate for static and dynamic thermal transients

Abstract: A method and apparatus utilizing a quartz crystal resonator with an orientation substantially equal to (yxwl) 21.93°/33.93° vibrating simultaneously in two thickness modes to accurately measure temperature and unknown frequencies or to provide a stable frequency signal source. By combining a quartz crystal resonator of the above type with either digital or analog compensation, the frequency-temperature deviation of one of the crystal mode frequencies is used as an internal thermometer and the second crystal mode frequency as a reference frequency signal. The frequency signal for the thermometer function is utilized by the compensation network to correct the measurements made with, or to stabilize, the frequency of the reference frequency signal. Additionally, the analog or digital compensation is accomplished by means of either a curve-fitting routine or an interpolation look-up table routine.

Transfer of Frequency Stability from an Atomic Frequency Reference to a Quartz-Crystal Oscillator

Abstract: This paper presents a study of the transfer of frequency stability from an atomic reference to a quartz-crystal oscillator. The study is done for the cases of active and passive atomic frequency standards in which one makes use of a phase-lock loop and of a frequency-lock loop, respectively. The analysis is made in both the frequency and time domains and covers the cases of the hydrogen and rubidium masers and the passive cesium-and rubidium-frequency standards. The results obtained from numerical calculations are presented under the form of graphs. These results include the fractional frequency spectral density Sy(f) as a function of the Fourier frequency f, and the two sample variance ?2(?) as a function of ?, the sampling time.

Crystal oscillator programmable with frequency-defining parameters

Abstract: A programmable crystal oscillator is provided having a memory for storing frequency-defining parameters. Typically, one of these parameters is used to program an adjustable capacitive load circuit coupled to a crystal to thereby adjust the crystal source frequency. Additional parameters are used to program the output frequency of a phase locked loop circuit coupled to receive the adjusted source frequency. A further parameter can also be used to divide the output frequency of the phase locked loop circuit to supply a specified output frequency. The oscillators can be manufactured as generic programmable crystal oscillators without regard for output frequency and then quickly programmed to produce customer-specified output frequencies with a high degree of accuracy.