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.

Electronic frequency stabilization of microwave oscillators.

Abstract: Two circuits for use to control the frequency of a microwave oscillator by an external high Q cavity are described. One of the circuits uses a microwave equivalent of the frequency discriminator, in conjunction with a d.c. amplifier. The other uses the cavity in a special circuit that provides an intermediate‐frequency signal that is a measure of the difference between the frequencies of the oscillator and cavity. This allows the use of an intermediate‐frequency amplifier. The resulting stability of the oscillators is such that audible beat frequencies can be produced between two oscillators at 10,000 Mc/sec. The resultant signal can be frequency modulated at audiofrequencies, with stabilization acting throughout the modulation cycle. A technique by which the frequency‐stabilization systems could be used to investigate, with high resolution, the structure of microwave absorption spectra is suggested.

A simple setup to simultaneously measure the resonant frequency and the absolute dissipation factor of a quartz crystal microbalance

Abstract: An experimental setup is described that can simultaneously measure the absolute dissipation factor and the resonant frequency of a short‐circuited quartz crystal microbalance The crystal is driven at approximately its resonant frequency by a signal generator which is intermittently disconnected by a relay, causing the crystal oscillation amplitude to decay exponentially The decay is measured using a ferrite toroid transformer One of the crystal leads is fed through the center of the ferrite toroid and thereby acts as the primary winding of the transformer The secondary winding of the transformer is connected to a digitizing oscilloscope which records the decay of the crystal oscillation From the recorded decay curve, the absolute dissipation factor (calculated from the decay time constant) and the series resonant frequency of the freely oscillating crystal are obtained Alternatively, the dissipation factor and resonant frequency can be measured for the crystal oscillating under open‐circuit conditions, ie, in the parallel mode The measurements are automated

Frequency stability degradation of an oscillator slaved to a periodically interrogated atomic resonator

Abstract: Atomic frequency standards using trapped ions or cold atoms work intrinsically in a pulsed mode. Theoretically and experimentally, this mode of operation has been shown to lead to a degradation of the frequency stability due to the frequency noise of the interrogation oscillator. In this paper a physical analysis of this effect has been made by evaluating the response of a two-level atom to the interrogation oscillator phase noise in Ramsey and multi-Rabi interrogation schemes using a standard quantum mechanical approach. This response is then used to calculate the degradation of the frequency stability of a pulsed atomic frequency standard such as an atomic fountain or an ion trap standard. Comparison is made to an experimental evaluation of this effect in the LPTF Cs fountain frequency standard, showing excellent agreement.

Local oscillator induced instabilities in trapped ion frequency standards

Abstract: The trapped ion frequency source is one of a class of passive atomic frequency standards that necessarily use an ancillary frequency source to interrogate the atomic transition. For passive atomic sources such as Rubidium standards, ultimate long term performance of the source is not dependent on this local oscillator, except to the extent limited by feedback gain. For the trapped ion source this immunity to local oscillator phase noise is lost. In contrast to the Rubidium source, a sequential measurement procedure is used in which the signal from the local oscillator is sensed only some of the time. Since the local oscillator is only periodically sampled, certain short term fluctuations in the local oscillator frequency will give rise to long term fluctuations in the difference between the stabilized local oscillator frequency and that of the atomic absorption. We have performed calculations of the influence of such phase noise fluctuations in the reference oscillator on the performance of the standard as a function of duty cycle for a local oscillator with frequency fluctuations showing a 1/f spectral density, as is typically shown by crystal Quartz oscillators for long measuring times (1-100 seconds). Expressions are generated for the limiting trapped ion -1/2 variance due to the local Oscillator for various values for the duty factor d. Explicitly treated are the cases d<1, d=1-6, (6 < 1) and d = 1/2. It is seen that for a duty factor < 90%, local Oscillator performance equal to that of the ion standard (for a measuring timer equal to the period te of the sampling cycle) will significantly degrade the characteristic 1-1/2 passive atomic standard performance. For d near 1, (6 = (1-d) < 1) an approximately linear dependence of this degradation on 6 is found.

Quartz crystal resonators and oscillators for frequency control and timing applications: A tutorial, revision 6.1

Abstract: : Subjects covered include: applications of frequency standards; types of oscillators (quartz and atomic); quartz resonator properties; quartz growing, sweeping, and material characteristics; Q and its significance; resonator and oscillator stability, including aging, short-term instability, frequency vs. temperature characteristics, oscillator circuit caused instabilities, frequency vs. drive level effects, acceleration effects, the effect of shock, and radiation effects; emerging technologies; atomic frequency standards; comparison of the major oscillator types; oscillator specifications and selection guidelines; time and timekeeping; clock errors; relativistic time; time transfer; time and frequency subsystem; and other applications of quartz resonators. The goal of this document is to assist in presenting to the nonspecialist the most frequently encountered concepts in frequency control and timing. The document originated as a set of hard copies of presentation visual graphs(i.e., vugraphs).... Quartz, Quartz crystal, Quartz resonator, Quartz oscillator, Resonator, Oscillator, Stability, Aging, Allan variance, Phase noise, Frequency control, Frequency standard, Clock, Time, Timekeeping, Atomic frequency standard, Rubidium standard, Cesium standard, Atomic resonator, Radiation effects, Vibration effects.