Topic
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.
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TL;DR: In this article, the average drift rate and cyclic variations of 2.5 and 5 Mc oscillators are compared to the atomic cesium resonance at 9.192631770 Gc.
Abstract: The present nearly universally accepted frequency standard is the atomic cesium resonance at 9.192631770 Gc. However, for many reasons it is not practical to use a cesium device for continuous frequency generation. Secondary frequency standards such as quartz-crystal controlled oscillators are commonly used for this purpose. Recent improvements in oscillator, oven and crystal unit design have produced crystal oscillators which require infrequent adjustment to maintain their frequency constant to a few parts in 1011 (pp 1011). This paper will present the performance of several of these oscillators and the state of the art in crystal unit fabrication and temperature control. The average drift rate and cyclic variations of 2.5 and 5 Mc oscillators will be given. The megacycle oscillators appear to have an average drift rate of less than 1 pp 1010/day while that of the 2.5-Mc oscillators is less than 1 pp 1011/day. The short-time stability (down to 10-msec period) of both types of units when measured in the kilomegacycle range appears to be of the order of a few parts in 1010. The effect of oven cycling and oscillator shutoff on the average drift rate has been measured. The period required for the frequency to stabilize after oven shutdown depends on the oven off-time. The oscillator frequency will return to a normal drift rate within 96 hours after a 24-hour shutdown, while it requires 5 to 6 days to return to a normal drift rate after a week shutdown.
21 citations
Patent•
19 Feb 1987
TL;DR: In this article, a short distance, battery powered, amplitude modulated, crystal controlled RF transmitter for transmitting encoded security information is described, where the transmitter comprises a novel fifth overtone crystal oscillator which self-produces a carrier frequency at the third harmonic of the 5 overtone of the crystal's fundamental frequency, which carrier frequency is coupled by a series resonant trap, or a pi network, tuned to the carrier frequency to an amplifier stage where the carrier is amplitude modulation via pulse position encoded binary security data.
Abstract: A short distance, battery powered, amplitude modulated, crystal controlled RF transmitter for transmitting encoded security information. In its preferred embodiments, the transmitter comprises a novel fifth overtone crystal oscillator which self-produces a carrier frequency at the third harmonic of the fifth overtone of the crystal's fundamental frequency, which carrier frequency is coupled by a series resonant trap, or a pi network, tuned to the carrier frequency to an amplifier stage where the carrier is amplitude modulated via pulse position encoded binary security data. In an alternative embodiment, the transmitter comprises matched crystal oscillator, tripler and amplifier stages. Also disclosed is an antenna including a battery clip contact.
21 citations
TL;DR: In this article, a simple oscillator circuit for high resolution quartz crystal microbalance sensors is proposed for fluid media, which can solve the working problems of standard crystal controlled oscillators in damping media.
Abstract: A simple oscillator circuit for high resolution quartz crystal microbalance sensors is proposed for fluid media. It can solve the working problems of standard crystal controlled oscillators in damping media. The design is adapted to the conditions of strong damping that the quartz experiences, so that the oscillation stays in spite of the reduction of the resonator quality factor. The conditions for obtaining a stable frequency according to the resonator damping and the static capacity are studied. Experimental results confirming the success ot the circuit are reported.
21 citations
Patent•
13 Jun 2007
TL;DR: In this paper, an oscillator having improved frequency stability is described, which includes an SC-cut resonator connected with the oscillator circuit, and a temperature compensation circuit is adapted to adjust a reference frequency generated by the oscillators according to a frequency response associated with a second turning point of an AT-cut Resonator.
Abstract: An oscillator having improved frequency stability which includes an oscillator circuit and an SC-cut resonator connected with the oscillator circuit. The SC-cut resonator has a first turning point. A temperature compensation circuit is connected with the oscillator circuit. The temperature compensation circuit is adapted to adjust a reference frequency generated by the oscillator circuit according to a frequency response associated with a second turning point of an AT-cut resonator.
20 citations
Patent•
06 Aug 1999
TL;DR: In this article, a crystal oscillator is coated with a layer of material having a sensitivity for hydrocarbons, which experiences a shift in its oscillation frequency relative to the fundamental resonance frequency.
Abstract: A vapor recovery system (18) utilizes a crystal oscillator (30) for sensing the presence of hydrocarbon in the vapor emissions emanating from a fuel tank (10) during refueling. The crystal oscillator (30) is coated with a layer of material having a sensitivity for hydrocarbon. In response to any interaction between the coating layer and hydrocarbon, the crystal oscillator (30) experiences a shift in its oscillation frequency relative to the fundamental resonance frequency. The frequency shift (34) is representative of the hydrocarbon concentration in the vapor emissions. A control signal (36) based on the frequency shift (34) is generated and then used to adjust the operating speed of a vapor pump (26).
20 citations